When playing in Franchise mode, visit the Free Agent screen and sign a free agent named Jordan Beck. He is a middle linebacker 71 overall. Change his position to defensive end and he will be 90 overall. The same thing works for most of the other linebackers when changed to defensive end. Also, you can change Ladainian Tomlinson's position to linebacker. Do this, then trade for him. He will have an F trade rating and his team will accept almost any player in a trade. When signed, release him and resign him to save cap room. Then, change his position back to running back. He will be 99 again. This can be done for lots of other players.
In Franchise mode, take any quarterback in the league (Peyton Manning is the highest overall). When you go to the roster and choose them, go to edit the player and change his position to a WR. He will have a 30 overall (if you selected Manning), and you can trade any pick or player for him.
Go to the "Trade" screen in "Roster Management" and go to your favorite team. Trade for very young players in every position, then edit them to the best stats and go to Franchise for a great team.