Funny Commentary
When you play against the computer and you're pitching, leave the controller alone and let the pitcher stand there for a couple of minutes and the commentaters will start making fun of you, and other things. This works with 2 players also, you just leave both of the controllers alone.

Extra Crowd Taunts
When you hit a homerun, on your trot home, hit Y X or B to do the extra crowd taunts. These are much better than the L and R taunts.

Press Y to wave your arm in the air in a victor march.
Press B to Clap hard and shake your head.
Press X to clap softly.

Easy hits
Pause game play immediately after the pitcher releases the ball. You will be able to see the pitching icon.

Easy season win
In season mode, go to the GM office, then go to the player editor. Set all your players to A+ then go to all the other teams and make their All-Star players a D-

Easy card points
Select quick play or franchise mode. Set the number of innings to 1 then score by any means while holding the CPU to a no hitter. When the single inning game ends, you will be awarded card points for having a perfect game and a no hitter.

Dominating team
If you have a franchise on this game, go to the main menu of franchise mode. Once there, go down to "GM Office", then go to "Roster Management". Select "Player Editor" and use the Left Analog-stick to move left or right to find your franchise team. After finding your team, the game will show a list of all the players on it. Go down to any one of them and you will be able edit their attributes to make them the best as possible. Do this to every one of your team members to dominate the league.

Homerun Hit
When you hit a homerun when your guy is coming home from third hit L or R or X to give a chant from the player.

Celebrations
After hitting a homerun, hold or tap the R trigger to blow kisses to the crowd and tap L trigger to do other celebrations.

Get Barry Bonds
Ok, so you see that on the Giants roster Barry isn't there, he signed some deal that said he couldn't be there this year. You see a guy named Wes Mailman right? Well he took Barry's spot. Just change his name and skin color and BOOM you have Barry Bonds