Hints:
More Homerun Angles: When the Batter is rounding 3rd after a homerun press various buttons to see new view angles
More Points: You can get points for doing various 'feats' in the game. To get 100 points easily you can pitch a perfect game by switching controls every time the CPU is up at bat and intentionally striking out.
Hitting Help: After the pitch is thrown press Start to see the ball path and whether it will be a ball or a strike. You can then adjust your swing accordingly.
Trade for any character: To get any player in season mode, play one game then create a player and make him 6'11" and any position except pitcher. Then set his patience, range, arm strength, arm accuracy, and glove to "D" and hitting, contact, power, bunt, and speed to "A+". When you pick him up from free agency he should be rated "A" (sometimes A-). You can now trade him for "A+" players.
