It's really a straightforward process so there isn't really much to get "tripped up" on unless you have some weird medical problem. That being said...
Get your letters of recommendation sorted out early. I was really lucky that the people I asked for LOR's (including even an O-6) were really generous since I basically needed them within just over a week. Just be direct and let them know what you need from them and when you need the LOR by.
Set up a study plan for the ASTB and give yourself at least 3 weeks of intense, focused studying if you can afford the time. Check out the ASTB thread here, but Kyle's study guide and the FAA handbook were my main sources of info. I used the Baron's book for the practice tests mainly. If you're going aviation, it's the ASTB is the number 1 aspect of your application that you want to focus on since its used as a predictor for success in the aviation pipeline. Taking it early allows you to still have time for a retest if you're not satisfied with your score. Setting up an ASTB date was pretty much the first thing my recruiter had me do after I sent her all my demographics and medical info.
(I just noticed your name lol, but the same still applies with regards to the OAR)
For the SF-86, if you've moved around alot in the past 7 years, reconnect with old friends in the places you've previously lived. You'll need a reference for each of your previous addresses and people who knew you around that time period. I transferred schools so it was kind of awkward tracking down my friends from the school I transferred out of who I haven't talked to in years.