It really depends, as there are so many variations of the deadlift. I'll break it down for ya into the three major variations I know; if anything I say is incorrect please feel free to correct me.
1) Traditional DL
Set up with an athletic stance (feet about shoulder width, you can go wider/narrower if you want, but this is a guideline). Pull your shoulder blades back and down (try to keep them there during the whole lift)
position the bar so that it is pretty much over your toes (I do this to avoid hitting my shins)
Brace your abs (not suck in); it should be essentially an isometric contraction.
Big breath in with abs tight. This creates thoracic pressure and helps stabilize the spine.
Bend first at the hips then at the knees, as if you were sitting back onto a chair (keeping the back straight).
Grab the bar with any grip you preffer. It can be wide, it can be narrow, but your hands are NOT between your legs. I preffer to supinate (grab palms up), but mixed grip or prone grip is fine too.
Keep your head in neutral alignment or slightly elevated (neutral being in line with the spine)
drive hard through the heels, making sure your hips do not rise before the bar does
As the bar moves off the floor and nears knee level, drive your hips forward with explosive force (as if you were about to smash the wall in front of you with your pelvis)
Lower the bar quickly in the reverse order of the lift. Bend at the hips first, then the knees (this swings the bar outward and avoids shin/knee scrape)
Once you get the traditional dl down, sumo is pretty much the same deal.
This time set your feet in a very wide stance, and grab the bar in between your legs (hands maybe 6 inches apart).
3) Romanian Dl
This is basically a half deadlift, all hip action. Grabbing the bar off a rack, bend at the hips until you feel a tight stretch in the hamstrings, then lift and repeat