Score Early - the best defense is putting the opponents behind early. If Tom Brady can guide the Patriots to a first possession score to put the Patriots ahead, it will put pressure eon the eagles to try to keep up. If the Eagles get eth ball first, New England has to force an early punt so they can get the ball back to the high-powered offense.
Stop Brian Westbrook - the majority of the eagles offense goes through Brian Westbrook, and if Philadelphia can find a way to get the ball to Westbrook early and often it will give the Eagles the best chance to stay competitive in the game.
Provide Solid Rush Defense - The Patriots have one of the best offenses and special teams in the league, but their rush defense has given up alarming chunks of yardage at times. No team has been able to exploit that susceptibility in the defense because they've been so far behind early. If Philadelphia can stay close, and run the ball is an option, than they need to exploit the matchups offered in the middle of the Patriots defense. With one of the best tackles in the league in Jon Runyan, it should be an easier tack to the left side.
Get the ball to Westbrook - much like the Patriots' need to stop Brian Westbrook, the Eagles need to exploit the Patriots weak rush defense on first down. New England gives up over 4 yards per carry on first down. If the Eagles can exploit that opportunity they might be able to make third down more manageable. The Patriots lead the league on third down defense with the top rated third down defense holding opponents to just 31.2% conversions.
Prevent the Big Play - If Philadelphia can stop the big play and make the Patriots a dink-and-dunk type attack, it will eat the clock and force the Patriots into a different style offense. It's also a way for the Eagles to control the scoreboard by preventing Randy Moss from putting the game out of reach early.
Get pressure on Tom Brady - there's no other way to say it. If you don't get pressure on Tom Brady, then whatever defense you're in will be exposed. The Patriots have far too many weapons to allow a quarterback like Tom Brady time to find the open receiver. The Eagles have the 8th best defense in the league (14th pass, 12th vs run). Philadelphia's 210 yards per game will be tested as New England is averaging 436 yard of offense with 305 thorough the air (best in the NFL).