Stay off their lawn
Google relies on its users to volunteer most of the information it collects. By visiting the Google website, you sacrifice a certain amount of privacy, in the same way that you do when you enter property belonging to someone else. What you do on my property is, to a certain extent, my business.
The easiest way to prevent Google from collecting information is to simply not go there. Don’t get a Gmail account, don’t sign on to YouTube, don’t install a Google toolbar on your machine. If you must use a search engine, do so from a computer that is not your own and is not operating on your home network or at your workplace.
Every website you use at least captures your IP address. Many more collect other data, through cookies, login information, or by tracking what you click on. The only sure-fire way to avoid this is to leave the Internet and never return. However, this strategy is only reasonable if you live in a cave or in the woods, and are content to avoid all human contact forever. Luckily, there are other steps you can take.