Don't let 'em see you, hear you, or smell you.
Don't let 'em see you: The old adage is the harder you hunt, the less you move. Avoid figets, jerking movements, or being in the open (stay behind something like a brushpile or some other cover.) Things like camo can help here, but not moving around is most important. Try to act like a stump.
Don't let 'em hear you: Dont talk, cough, bang things, etc. Be as quiet as possible moving in an out of position.
Don't let 'em smell you: stay upwind or at least have it quartering from where the deer will be. There are scent control products that may help, but wind-in-your-face is #1.