Originally Posted by
autopsy
Learn the quest progression of each zone, knowing which quests are optional, which quests will be a bottle-kneck on a largely populated area etc.
Some quests from hubs are not required to complete to move on to next hub. Skipping these can get you ahead of the crowd and make it alot smoother when not competeing for spawns.
Have at least a tank and healer at hand for quick dungeon runs (preferably a full group to run with).
Keep a supply of enchants / gems / food / flasks / potions in your bags.
Disable non-critical addons. By the time of launch most addons will be updated for the new stuff added in the pre-launch patch so broken / lua errors wont be a problem but, depending on your machine, loading times can be. An addon that auto-accepts / turns in quests, skipping all quest dialog is a nice thing to have.
outside of the game:
snacks + drinks; sandwiches + OJ.
A good playlist
get on vent / skype etc with friends + guild. A bit of banter is always an exellent thing.
Hope you aren't stuck out of the game for several hours due to login server issues while others can get on. This is probably one of the biggest problems you might face. Can remember cata launch, when I finally could login I did a /who and saw several folk already lvl82.