I am not a good hitter, but I get by. Here are my suggestions:
Play the CPU on Rookie until you get your timing down. This will give you more balls in the strike zone than more difficult levels. Once you feel confident on Rookie, move to All-Star. The batting will be a little more difficult and you'll see more balls out of the strike zone, but not a lot. This will help you watch the ball better. Once you're comfortable on AS, move to Veteran, and so on. Right now, the Rockies, White Sox, and A's have the worst pitching attributes and are easier to hit than...say...the Dodgers, Braves, or Astros.
I have my Hitting and Pitching views both on Strike Zone 3. This way, I see the ball the same way twice as much and it has helped me to gauge balls and strikes (a little) better.
I watched a tip online that said that by watching the ball release in the first 5-6 frames you will be able to tell (99% of the time) if the ball is outside or inside the strike zone. If the ball crosses the pitcher's body in those frames, it will be outside. If the ball stays outside his shoulder it will be inside (depending on if the batter is R or L the inside and outside part will swap).