I went on amazon and just ordered as many different books with sample tests in them. I was so busy in clinic, etc. That I made it through one book, and half of the other. Be sure you study the ob, peds, and psych. Those are the heaviest that I didn't have a lot of experience with. Of course there is surg, and IM that is the bulk of the thing. Just do lots of questions.
If you do OMT all the time, don't even bother studying that. The practical is super easy, they pass everyone.
Use swansons and you'll be fully overprepared for COMLEX IV, I mean the FP boards. . The practical is cake. OMM notes from med school helped me pass that. The only drawback is having to travel wherever it's being held.
Of course you'll also be required to write two board questions with references and citations.