Don't give up in the run/pass commit just yet. It'll take some practice in single player and you'll only get a split second after the snap but once, you get it down it's invaluable.
The CENTER ALWAYS GIVES THE PLAY AWAY. You can get fooled by the pulling guards but watch the center. Don't move your line pre-snap or crash or slant or anything. Just let them set and watch the center's movements. If he pops up with his hands up and slides one way or another in a pass stance, it's playaction. It he fires out low into a block, it's a run.
The key is don't move your d-line unless you're definitely sure what kinda play is coming. The movements in the game aren't perfect but the little keys are there if you know where to look.