I hope my experience might be helpful especially to someone like me who has spent close to 6 years out of the academy and is looking to go back.
I'll start off by mentioning that my cycle has been a bloodbath so far. Given that my GRE/GPA was good, the obvious culprits are a deficient writing sample, bad LoRs, bad SOPs and/or just a lack of easily referenced experience compared to someone coming out of an MA program or undergrad with publications. I suspect all played a part, but I'll address them all briefly.
1. Writing Sample - find a professor, or someone as close to the academy that you can find that can both edit and advise what kind of paper you should submit. This will be harder if you are removed from school or your professors aren't interested in related fields. Both of these factors were a problem for me, so I recruited a friend who was a doctoral student in English and an expert in a related but nonphilosophical field to read and give my paper notes. These were helpful, and my paper was much better for it, but it probably was still not up to journal quality, which is what you should be aiming for, and I feel as though only the guidance of an actual philosophy professor with familiarity of the topic could have gotten me there. Take advantage if you are still in undergrad (or graduated recently) or have such a professor in close proximity. For the rest of us, you're gonna have to work much, much harder. Go to conferences, go to office hours of professors you don't know, take off/skip work if you have to. Otherwise, you better be really really good if you want to go straight to a PhD program.
2. LoRs - not much to be said here. Soliciting professors who half remember me from 6-7 years ago was always likely to be a problem, but there was not much else to be done here. Get to know your professors and keep in regular contact with them if you think grad school is even a remote possibility. This was probably significant given that I would assume 2/3 of my letters were "this student took my class and he was fine," but I don't know what else I could have realistically done on this front. The only way to realistically fix this problem is to get your MA first or audit classes locally.
3. SOPs - I'm curious to hear what advice people have on this subject. I don't have much to add here.
4. Experience - Attend conferences (if you can), address on going projects (if you have them), mention your publications (if you have them). If none of these apply, try to get them ASAP.
Get your sample paper done early and leave plenty of time for editing.
Be ready if you need different versions of your paper for different length requirements.
Save ~$85 per application (don't forget you gotta send your GRE scores)
The accepted wisdom is definitely true that good GRE/GPA is (basically) necessary, but far from sufficient. These aren't law school apps.