If you have the time and the funds.
I would say visit the key locations you would like to attend.
If accepted you will be living the next several years there for the most important stage of your liffe so-far.
You want to feel comfortable and from a womans point, safe with the area.
If you are targeting an area in the country that you would like to live long term, that may not be were you currently live, you want to get the "feel" of the region.
Depending on the level of visit or interview you can arrange, you will want to be prepared with specific questions.
The questions, should not be only about what the school can offer you in opprotunities, be prepared to emmerse yourself in the environment and what you can bring to the program.
My brother and I are close, I was very active in his visits.
Be positive, be attentive, learn about the school, the town, the culture of the university, the professor's you will interact with.
Personality match is key, do not attend somewhere just because it is higly rated, attend a quality school close to the rank of the high rank but does not feel right.
You should leave the University inspired, fired up praying you are accepted, if you do not than it is not for you.
You will have doubts and feel a little overwhelmed, that is good, that means you value the experience.
Challenge yourself, that is why we attend Grad school, to get better and be prepared for our goals.
Be prepared for relationship issues, with you BF/GF you will be challenged in ways and time constraints you can never expect.
Discuss this with your BF/GF prior to leaving for Grad school. It is tough enough starting grad school emotional strains and relationsionship issues can really effect your studies.
I hope these help, a little different take than the "questions" you should ask.
I f you are confortable with the environoment you will do your best work, it should not be a labor just to live or survive the experience.
Grad school is tough enough as it is do not make daily life a emotional drag itself.