If it is going to be a close play at the plate for your base runner, tap Down repeatedly to barrel into the catcher. The collision may knock the ball loose.
Batting
The closer you get the center of your batting cursor to the center of the ball, the more power you get out of your swing.
Throws
Aggressive throws are by nature less accurate than normal throws. Save them for when you have to make the big play.
Pitching
Keep an eye on the pitcher's energy level. When the pitcher gets tired, consider bringing in a reliever. The more heat he throws, the more tired your pitcher gets.
Hide the ball
Press R1 when you are pitching to hide the ball.
Easy strikeouts
Note: The following trick will not work in All-Star mode. Throw your fastball at full power and a breaking pitch (slider or curveball). If you have a right hander, throw the first pitch high and inside to a batter. Throw the second pitch coming across your body (for example, with a right hander to the right side of screen -- player's right) low and outside/inside depending on the batter (left or right hitter). The first two pitches should both be fastballs. Throw the third pitch as a breaking ball going away from your body (for example, with a right hander to the left side of screen -- players left) low and outside/inside (again depending on batter). Give a little bit of movement towards the end of all these pitches with the Analog-stick. If done correctly, your strikeouts will increase.
Super defense
Execute three double plays in one game.
Small players
Get over eleven hits in one game.
Fast players
Steal three bases with the same player in one game.
Big glove
Catch a homerun as it is going over the fence.
Bigger ball
Get six strike outs in one game.
Big ball
Get three strike outs in one game.
Big bat
Hit two consecutive home runs.
Homerun sounds
Press X to hear air horns while running around the bases after hitting a homerun. Note: Set the Sound FX volume to maximum for best results.