Nickman20

Ditto! At last the wait is finally over! Well done to everyone. Don't feel too down about the rejection. I have followed the stories of some  Gates Scholars/alums and discovered that they didn't even get shortlisted the first time they applied! I think if we're all  good enough to get into Cambridge - one of the best institutions in the world - then we're equally good enough to go out and do some great things in the world. 
Good luck to everyone here who got an invite.  I'm rooting for you all!

Okay, I told myself if I won, I would be certain to leave the web with more useful information than I have found. Here are a few tips for future applicants. These are my personal tips, based on my journey; I encourage you to sift through, find what is useful and chuck what you think is not. 
1. From the moment you start your application you need be aware that you are tailoring it for two different audiences- the department you are applying to and the Gates Cambridge committee. These audiences are looking for some of the same things as far as academic excellence and leadership (this, after all, is what will get you moved to Gates), but Gates is incredibly mission-driven and in this way it may differ from your department. Your application needs to take into account the Gates mission and needs to deeply tie the Gates mission with the work you plan to do long term and the program you plan to pursue at Cambridge. 
2. Practice your interview- I am not one who struggles with interviews at all, but I found that there were many "blind spots" I had not considered when preparing for my interview. This is where practice interviews with my undergraduate institution were incredibly helpful. They were able to ask me questions and raise my awareness of even small things like word choice. It is useful to get a different set of eyes on your interview preparation. 
3. By the time you get to the interview- everyone is excellent. We are all equally yoked as far as accomplishment, intelligence, department support, and mission. Thus, the interview is a chance to stand out from the pack. It's a chance to sell your passion for both the work you intend to do and also for becoming a part of the Gates community. Be sure that you are prepared to speak to both. Gates Cambridge has a youtube page which you may find useful and of course, you should be LIVING on the Gates Cambridge website. You are mainly trying to prepare yourself to convincingly argue that you are an amazing fit for not only your program, but for Gates. 
4. Have fun- the interview IS going to be an amazingly friendly and personable interview. Be personable, passionate, informed and friendly. Come ready to enjoy the dialogue. 
5. Take comfort in knowing that you are now incredibly competitive for other University/college funding- I was told that funding entities tend to like to pull the names of Gates interviewees who did not win- they do so because they can be certain of the quality of applicant. 

I got it !!!!!! I am so excited I literally cried. 

Why did you post in the results thread if you haven't applied to these programs yet?

I think you have a very good shot at all of them.
From the UK perpective. Obviosly Oxford and Cambridge are in a league of their own. LSE is the next best academically but it's famously bad for extra-curricular, sport and social life. Edinburgh is a great all round university. KCL has an inflated international reputation but it's not seen as a very good university dometically (it only ranks 21st).
I'm guessing these are the top 5 UK unis occoring to Global rankings?? Have you consided St. Andrews or Durham? They have better domestic reputations than LSE, Endiburgh or KCL. SOAS is well known for IR too. 
So yeah domestic reputation wise: Oxford, Cambridge,... (big gap)... Durham, St Andrews, LSE,... (small gap)... Edinburgh, SOAS... (big gap)... KCL

Your experience is amazing. Your GPA is not unflattering, but it could be better. I believe that you would be able to gain acceptance to at least 2 of those programs. 

PROFILE:
Type of Undergrad Institution: Comprehensive Canadian University
Major(s)/Minor(s): Political Science & Legal Studies Option 
Undergrad GPA: 3.84/4.00
Type of Grad: I am applying for Masters
Grad GPA: N/A
GRE: Did not have to complete 
Letters of Recommendation: 2 tenured professors in Political Science department; 2 assistant professors (non-tenure track)
Research Experience: 2 published journal articles & undergrad senior research project.
Teaching Experience: Worked as a TA for 4 classes (4 in undergrad)
Work Experience: Policy Intern at Canadian Embassy in Washington D.C, Legal Intern at a top 20 international firm, and an analyst at a Fortune 500 company. 
Subfield/Research Interests: IR
RESULTS:
Acceptances ($$ or no $$): LSE ($$), UCL ($$), St. Andrews ($$), SOAS ($$), Cambridge ($$), Edinburgh ($$)
Waitlists: 
Rejections: Oxford
Going to: Deciding between LSE, Cambridge, Edinburgh, & St. Andrews (Leaning towards LSE/Cambridge)
LESSONS LEARNED: 
DO NOT APPLY LATE TO YOUR DREAM PROGRAM. Goodbye Oxford  

PROFILE:
Type of Undergrad Institution: Large, high-rank R1 State school
Major(s)/Minor(s): Political Science major, statistics minor
Undergrad GPA: 3.74
Type of Grad: N/A
Grad GPA: N/A
GRE: V168 Q162 AWA 4.5
Any Special Courses: One PhD-level course in survey/questionnaire design, two courses in the first year graduate student statistics sequence, plus Calc 2 and Calc 3 (the C in the former is the biggest mark on what was otherwise a good transcript)
Letters of Recommendation: Four Tenured or TT Poli Sci faculty, three of which I served as research assistants for at some point, each worked in different subfields (CP, IR, and AP). One is the DGS for my school. Alternated between sending the CP letter and a different AP professor who I didn't do research for but was personally close to and who I often talked about research with, always sent the letter of the DGS and my thesis advisor.
Research Experience: RA'd for four different professors, first projects involved literature review work for two of them, one of which was a big name but rarely got to talk to or get close to and because the work I did was relatively insignificant and because we fell out of touch never asked for a LOR. Third project involved a lot of tracking down of replication data files and R coding for visualizing dozens of results. Fourth project involved interviewing a couple dozen subjects, ended up writing a portion of the final paper and receiving a co-authorship on a conference paper we presented at MPSA 2016, we weren't able to get it published but was able to put a (Under Review) paper on my CV during application process. Did a senior thesis on MTurk survey data that I presented at a poster session at PolMeth 2016. Worked as an editor for an undergraduate research journal.
Teaching Experience: TA'd for one of the professors that I RA'd for.
Subfield/Research Interests: AP (public opinion, information effects, machine learning)
Other: Did an internship during 2016 summer at a news organization that had some "cool" factor
 
RESULTS:
Acceptances ($$ or no $$): UC Berkeley ($$), Chicago ($$), Yale ($$)
Waitlists: Princeton
Rejections: Michigan, Stanford, Stanford GSB, Harvard
Pending: N/A
Going to: Not sure yet, going to come down to campus visits because having chemistry with my advisors and cohort is the highest priority for me, I definitely draw a lot of motivational energy from other passionate and energetic people.
 
LESSONS LEARNED:
- I wish I had polished my thesis/writing sample far more than I had. It makes sense for it to be not fully polished during the first months of my senior year during application season, but what I submitted was essentially a first draft and it certainly wasn't my best work, I just felt like it was better to send a research article-like piece of writing rather than what would have been a more polished piece of writing but what would've just been an obvious term paper. I don't think I was wrong in that assumption, but I definitely could've spent less time procrastinating by formatting and reformatting my CV and polishing my writing sample.
- I also think I spent far too much time in my SOP covering my qualifications rather than talking about what I wanted to research, why, and how. I do think I avoided most if not all of the "Kisses of Death" so often referenced, but I think I should've let my CV do the talking as far as qualifications go, and used my SOP to talk more about motivations and ideas. I'll admit that while I sought advice from my letter writers about writing my SOP, I never had them read it before I submitted my applications, which I think was a mistake.
- Others have talked about this in the main admissions thread, but I found it interesting to notice how my preferences changed as admissions results rolled in. While I was applying I always had a mental tier list of where I most wanted to go, but that tier list changed quite a bit as the cycle went along, with one of the schools I considered to be dead last on my preference list currently being my favorite among the places I was accepted.
- I was very fortunate to get early success during the cycle (Berkeley and Chicago were among the first to send out decisions) which made the rest of the cycle go easier, but despite that, it's still emotionally exhausting to get denied from a place you'd spent so many months fantasizing about attending (Stanford GSB and Harvard were my two top choices and I definitely spent an embarrassing amount of time stalking the faculty pages/websites of my fantasy advisors during the cycle)
 
SOP: Rather not share my SOP because there's definitely some things that could easily identify me with a modicum of effort even if I redacted the names of people/institutions.
1st ¶: Stated my name, intended program and subfield, and my specific research interests.
2nd and 3rd ¶: Told a brief story about the juxtaposition between my experience at my media internship and presenting my research, how it motivated me to pursue grad school.
4th ¶: Summarized how my grad-level and quantitative coursework has prepared me for graduate study
5th and 6th¶: Talked about my RA experience.
7th ¶: Described my thesis research.
8th ¶: Described my TAing experience and my experience editing for an undergraduate research journal
9th ¶: Talked about the department and why I thought I was a good fit. On advice of my DGS letter writer I made sure that professors were not noted in alphabetical order to avoid appearance of simply scanning the faculty list.
Each letter ended up being about 1100 words.
Happy to answer any questions, would also love to get in contact with anyone visiting my accepted schools.

The one thing to bear in mind is that if your preference is to do a PhD, and you intend to apply to US programs after completing your MPhil, you might have a rough go of things. Top US PhD programs don't like that the Oxbridge system doesn't teach any (if at all) formal or statistical methods, especially in the applied sense. This isn't to say it's impossible, but you might find it a sharp adjustment to your research, with the requirement that you pick up a lot of math that Oxbridge won't require you to even glance at.
If your long term goal is to work in public service, an MPhil will likely suffice. You might want to look into MPA or MPP programs as well. Certain Canadian universities are well connected to many of the programs you applied in the sense that graduates from McGill, for instance, don't tend to have issues getting into LSE or Oxford. 

@Nickman20 I'm also a Canadian undergrad and was recently accepted to the MSc Global Governance and Diplomacy (a taught degree in the IR field). I think that a big part of being competitive is your work experience and research interests. I'm doing my undergrad thesis in a topic similar to one being undertaken by the department to which I was accepted, and I applied with a clear statement of what I want to research at the masters level and why it is best suited to the program. Simply wanting to go to the most prestigious program will likely not be enough for admission. I also have several years of political experience that I used to my advantage because it explains my background and interest in the research I would like to undertake. In that regard you can use that experiences in the workplace and abroad to your advantage. One place you might struggle with (for Oxford at least) is the GPA requirement - I have a 4.0 and am required to maintain at least a 3.8 GPA after graduation to keep my offer. 
Hope this helps!
 

I would give reputation but I'm capped at 5 a day.

"Best opportunities for careers in academia, careers in policy, and foreign service that I could receive entry into."
Completely different things. What exactly are your goals? Why do you want to do programs in IR? What are you hoping to achieve?
That being said, generally these types of master's programs are not that difficult to get into.