Play a game with the San Francisco Giants. When it is Barry's turn at bat, set him to swing in either of the lower areas (A or B.) Wait for a nice pitch down there and hold UP while you swing. If you did it right you'll hit a homerun about 75% of the time.
Big Heads
Hit a homerun. While the ball is in the air, hold X + Y + Z + A + B + C + L + R + Right.
Easy Base Hit
Bunt down the first base line with any batter batting left with a speed of B or better, then repeatedly press the C button until you're safe. This play works about 90% of the time.
Easy Outs
In the classic Homerun Derby, press and hold UP before the pitcher throws to the hitter. This will make the pitcher throw high and it will count as an out.