Paul's got some great advice for folks considering applying to PhD programs, advice worth repeating every year round this time, which is about when the cycle begins in earnest. I've already replied to several inquiries, and expect plenty more. I'd add a few things to his list as well, speaking as someone who's been involved in the process from the committee end for a few years now. So in addition to Paul's 10 points:
Writing Sample: This is one that I think gets misunderstood. Sometimes I see applications where a sample is submitted straight from a course. It doesn't occur to some applicants that it's okay to revise a seminar paper, even after it's been submitted for a course. Every applicant should be asking his or her mentors for feedback on a draft of the writing sample, which is one of the single most important parts of the application (for us, at least).
Searching for Mentors: It's important to find good people to work with, but it's almost equally important to find a program that supports that kind of work. One way to figure this out is to look at recent dissertations. Each of those projects required anywhere from 3 to 5 members of the program, and it's a good sign (above and beyond an individual professor's specialty) when dissertations in your areas of interest are coming out of a program.
Strengths and weaknesses: I'm not a big believer in wearing one's weaknesses on one's sleeve, but be honest with yourself about what you're good at and what you need help with. A program that caters to your strengths will do you good, but one that does so while also helping you shore up other areas will do you great. Both this point and the last one speak to the fact that joining a program will almost always mean doing some of your work (coursework, research, etc.) outside of your immediate interests.
Self-promotion: It's worth repeating what Paul says about this:
You don't have to sell yourself too much--this is not a job application. Being a good student and colleague who will successfully and promptly complete the degree and become a successful member of the field is sufficient.
I see a lot of spin, as you might imagine. The thing about that, though, is that it's not that difficult to see who's bluffing and who's not. Be straightforward about what you've done and what you'd like to do, and that's often enough. I feel about this the same way that I feel about "personalizing" job application letters which, despite some folks' advice, I never do myself nor advise others to do. I've served on admissions committees and search committees galore, and I've never been in a situation where an otherwise unqualified applicant was given special consideration for their personalization of a statement or app letter.
Asking questions: I hardly ever tell someone, in reply to a question, to go read the website, but that doesn't mean that I don't get those kinds of questions. And honestly, it affects how I look at a candidate if that person asks something that a quick trip to the website would answer. We don't put everything up there, by any means, but we do try to share as much information as we can for prospective students.
That's all I can think of off the top of my head. I'd double plus bold italic underline Paul's first point, though: be sure that doctoral work is for you. It requires a mix of passion, stubbornness, persistence, and interest that is not everyone's cup of tea. If you're at a PhD program already as an MA student, and looking elsewhere, look at your doctoral-level colleagues, and make sure that you can envision yourself doing what they're doing. There are lots of people who don't feel that the rewards of a doctoral program are worth the personal, psychological, and social costs. Be as honest with yourself as you can about your reasons for applying, and make sure that it's the right decision for you.
That's all. Happilicationalizing.