I got a couple..
I played DE and I used to hit the guy in the helmet with my hand, he should move a little bit, he might try to hold you from getting there, if he grabs your jersey, try falling on him, ref might see it. Penalty
Watch Reggie White and watch his arm throw. He used to get his right arm under the left armpit of the OT and toss them to the side. Requires strength but definately effective and clean
Another one is, if you bullrush the guy, hit him the gut first then push the bastard out of your way.
Last but not least, drive the bus! Grab the to pieces on the shoulder pads that cover the upper part of your chest, grab the sides of those bitches and he is yours. Push like all hell, hes yours if you got the steering wheel.
Driving the bus was my favorite. Talk some shit to the guy in front of you at the line. Ever watch 'The Program'? EXCELLENT football movie. A little old (early 90's) but its awesome. Listen to some of the things Alvin Mack says on it and use it. I always did. Good luck to you man!