Get Tons of Points
Start a two-player game and proceed to strike out every batter on each side until the bottom of the ninth inning.
When you've got two outs at the bottom of the ninth, walk the next four hitters to earn enough points to buy 100 card packs, which should get you almost every card. If not, repeat and get yourself more card packs.
NOTE: This doesn't include special cards earned in Scenario Mode.
Hint: Easy Hits
When your up at bat, press square to get power. Right when the pitcher throws the ball, press pause. Look at where the ball is. Resume back to the game and move the target to the ball. You will get good hits.
