1. Check all the blogs and online sneaker forums that you can.
Sneaker forums are your heads up for all things having to do with a line up. You will get information on what stores will be getting the coveted shoe and what time the store will be opening. Sometimes you may even get an estimate as to how many pairs a store will receive. Naturally a store like House of Hoops will get more pairs than your local Foot Locker based on size alone, but the forums may put you up on the stores that you never thought would get a pair.
2. Form Your Crew
Chances are you are not the only sneakerhead in your group of friends. Make sure you guys have agreed on a time and go out there together. There is strength in numbers, and better yet, there is always someone to talk to during your adventure.
If you happen to go to the line by yourself, you have one thing in common with everyone there, so you will be able to make friends quickly. If all you have to talk about are sneakers then start there. Eventually you'll develop a friend who will hold your spot in line down whenever you have to leave for a few minutes (or hours).
3. Pack Well
It doesn't matter how warm it is, you will need to pack something warm for the night. Once your body temperature drops, staying outside will be miserable. Bring extra socks and underwear for freshness, and if you plan on being out there for days at a time, pack a toothbrush and mouthwash. Nobody wants to talk to the kid with the horrible breath on the sneaker line.