1. Network widely. Get to know your Noogler class, and setup lunch/dinners with them for a few months after Noogler training ends. Get to know the folks who sit around you, and eat with them. Try to meet folks in other departments as well. Your network will probably be your single biggest asset in trying to navigate Google's often byzantine project structure.
2. Your starter project will probably be pretty boring. Suck it up and do a bang-up job on it. Starter projects are usually a way for your team to get a sense of what you can do. If you establish a reputation as someone who gets shit done early on, good projects will come your way.
3. Stay away from - well, I can't exactly say in a public forum, but basically any mailing list or internal app where you get long centithreads or pictures of cats. Corp G+, however, is pretty useful for getting plugged in to what the general zeitgeist at the company is - what concerns the rank & file employees have, what projects people are excited about, interesting new infrastructure that's available, teams you may want to join.
4. 20% time is a great tool for getting to know a potential team and letting them get to know you, and a terrible tool for starting something new. When you first start, you should probably be heads-down on your main project, and dive in there. But once you've got a chance to see some of the other interesting projects in the company, don't be afraid to 20% there and transfer if you like the experience.
5. Find and attach yourself to a good manager, do good work for him, and ride the coattails of shared success. Managers vary wildly in quality at Google. Experienced engineers (those with >1 year of experience in a department) all know who the good ones are. If you get a bad manager you will stagnate, find your projects are continually ripped out from under you, and come up short at promo time. If you get a good manager your career will be one success after another, and eventually you'll get a reputation as the "go to" guy in a domain. That's when you get your pick of high-profile projects.