Unlimited first downs:
Get a 1st and inches (1 and 0 to go) and stay on the 0 yard line.
Easy gains:
Select a game 1 in one player mode. Get the kickoff at approximately the 15 yard line. Run the ball back down the middle of the field. Wait and allow the blockers hold the other team. Then, run almost out of bounds at the far right side of the field. If done correctly, there will is be a small gap between that final free defensive player and the out of bounds. Run down screen and through the small gap. You can return the ball from kickoff to about your opponent's 20 yard line. This can be repeated as needed, since the CPU team always kicks off to your team.
