Better Offensive Players:
Create three WR with a height of 7'0", weight 220 lbs., and stats at 0 for upper and lower body. Set everything else to 100. 

Better Defensive Players:
Create two players with a height of 7'0", weight 220 lbs., and stats at 30 for upper and lower body. Set everything else to 100 except jumping and block. Thrown ball should be 95 and intelligence 50. 

Easy Sacks:
When on defense go to 3-4 and select "Base". When on the field, select your outside linebacker and move him close to the line without crossing the line of scrimmage. Once the QB snaps the ball, use speed burst to run around and sack him. This works well unless there is a TE were your LB is located. 

100 Rated Players:
To create a 100 rated RB, set the upper and lower body strength low enough to put all the other stats at 100. Then fill up the rest on your upper or lower body strength. The same can be done for a QB, TE, WR, DB, LB, DT, DE. Just make sure that your LB, DT, DE are bigger. For a DT or DE set the weight to 400 lbs. and height about 6' 0". For the LB, set the weight at about 260 lbs. and make him 6' 4".