If you're having trouble, don't worry about the right stick. It's used to influence ground balls or fly balls, but it's not necessary to hit well. If you're playing all-star or higher, you will need to move the left stick to where the ball is pitched (on rookie & veteran, it doesn't really matter much). You can still make contact if, for example, you move the stick to an outside pitch but the pitch actually comes inside, but in this case your contact will be weak and you'll likely pop up or hit a dribbler.
The thing that helped me the most was going into practice and turning on the batting API (the yellow circle that shows your plate coverage) -- this helped me see how moving the left stick was impacting my swings. I also had the pitcher throw only fastballs so I could work on my timing and laying off bad pitches without having to worry about determining which pitch was coming