As other have said, put your requests in order that you want/hope to get because you don't know, nor have any control/insight on what the others in your class want or will put down. That being said, "surprises" happen...as a 06xx I expected to get my last choice or thereabouts but was fortunate (and shocked) to get my first choice (SEA 220). I prioritized domicile, followed by a/c that are based in SEA and would allow a base transfer if necessary, followed by western bases, Midwest, and East Coast. Those were my specific wants/needs based off of commuting, family, the very little I knew about certain a/c schedules and what seemed to make sense at the time etc. Apparently my class had more people "senior" to me that wanted E. Coast, DTW, MSP etc.

Best of luck. Don't forget you're more senior than the 99xx in the class that starts the week after you!