Haha! Me being one of those 1800+ and beating even the 7th best player two days ago (Rating 1995)....
Here is my advice.
Keep your left thumb still for the most part! Concentrate in balls down the middle of the plate and move the stick a bit if the ball is in the corner is anywhere else.
This is key. Sometimes we concentrate so much in hitting the good pitches, that we miss the meatballs.
I have zero problem with fastball, my main problem is when people throw 90% change up, curve and sliders in the corners...those are the tough ones to hit.
You come at me with fastballs and you're going to have a bad time.