Hi MarkusHalberstram,
You've given yourself plenty of time to study, which is good. The 750+ score level is one that most Test Takers are incapable of achieving. It requires a combination of knowledge, Tactics and execution. While you can certainly start off your studies with whatever resources you choose, there really isn't a 'checklist to 750.'
The main OG is a great source for practice questions, but it's not designed to teach you Tactics, patterns or the 'secrets' of the GMAT. You'll likely find having one of those books to be useful, but you'll need plenty of additional resources to go along with it.
1) Have you done any studying so far or are you literally just beginning?
2) You'll likely need 3 months (or more) of consistent study time to hit your 'peak score', so are you planning to start studying full-time now or later on?
GMAT assassins aren't born, they're made,
Rich