Probably worth getting someone in with OO design knowledge (doesn't have to be in ABAP) to check out what solutions you come up with. Even if it costs a bit extra in the short term, in the long term it could be an excellent investment. Perhaps you can get it paid for out of the training budget - "hands-on training".
I learn OO through Java, and then applied what I learned to ABAP Objects. My first few attempts weren't brilliant, but not disastrous either. You should soon pick it up. Two tips:
1. Don't be afraid to refactor when you've gone down the wrong route
2. If you find you have to refactor and it is difficult - that's a sign you've done something wrong, and really need to redesign!