All-Star player
Start a season. Select the "Cheats" option at the seasons main menu. Enter Touchdown as a code to unlock an All-Star player to place on your team.
Raising stats
After you play a game in season mode, go to the newspaper and press A, B, A(2). Then, choose to either raise your offense speed by one, your defense strength by one, or your special teams agility by one. This may be repeated as many times as needed.
Various Codes
Go to season play, go to the cheat code selection, and then enter each of these cheats to build a team of fictional players:
CIRCUIT FUN, BAMPLYR, TARGETSTAR, SIKPOWER, EBPLAYER, SIKSTAR, TOUCHDOWN, RZONESTAR, BESTBUYPWR