Congratulations on the new Pitts - it will teach you a tremendous amount about aerobatics.At the risk of being pedantic, there are two things you must have to become a better aerobatic pilot:
1) practice. Lots of it. One, maximum two short (eg 0.5 hours) aerobatic flights every day if you can. There is an old saying in IAC cirles about the best pilot being the one who has put the most 100LL through his engine
2) critiquing. Without critiquing, you will likely end up practicing your errors over and over again. The more critiquing you can get, the faster you will improve. One of the major benefits of attending a contest is the comments on the judge's score sheet. Bring them home, read them. Without a box at an airport, it can be very difficult to get any critiquing ... you need to get someone to travel out to where your aerobatic box is located. Get several people together to make the critiquer's trip to the box worthwhile. Most of us don't have the luxury of attending a week-long "training camp" where you and the other students fly, fly, fly all week long and get expert critiquing every day, all day. But, that's how you get good at contest aerobatics.
Last comment: get a sight. Get a really big sight. Get two really big sights, one for the right as well as the left. Spend the time to set them up correctly for wing drag on the vertical.
And remember, have fun!!