100 rated players
During a season, go to "Settings" and turn salary caps off. Then, go to "Manage Roster", and make or edit a player. You can put all their stats to 100.

Extra teams and stadiums
Keep collecting cards until you get some stadiums and teams.

Random team selection
Select exhibition mode. Press L to choose a random visiting or R to get a random home team at the team selection screen.

Skip coin toss
Repeatedly press A + Start + Z (about five to six times) at the coin toss screen to advance to the kickoff.