Watching Gerrard must be the most pointless exercise in the world if you want to learn the basics of being a central midfielder. It's like watching Roberto Carlos if you're a leftback - it doesn't help your legs to become tree trunks and watching Gerrard won't help your aerobic endurance to get to the level that he has.
The prototype isn't Vieira or Gerrard, it's Makalele
Easily the craftiest and most efficient player out of the three, and I dare say possibly the best player by allowing everyone else in the team to play. It requires a level of appreciation that's Zen though, even Robbie Savage might work as the model of how to get the best out of your talent. Kick people, be dirty, dive when you lose possession, etc.
Also when the ball is being carried towards you, whatever you do, don't be moving fast (i.e. run towards him) because a good 7 yo can beat you just by changing direction. When he's close enough that he has to play the ball either by passing or by trying to dribble past you, take a step forward, cut off the angle and/or BREAK HIS #%[email protected]
The very most important attribute to a good central midfielder is all in his head. Knowing when to pressure, when to drop off, where your team-mates are and if they have them covered, where to run and where to pass to. The key technical requirement is a good first touch. If you have the ball going where you want it to 99/100, you can play for Real Madrid