The Electronic Frontier Foundation isn't happy with Google's plan to expand its use of the information it gleans about you, and it provides a quick four-step process on how to keep that data more private. "Until now, your Google Web History (your Google searches and sites visited) was cordoned off from Google's other products," explains EFF. That changes March 1, when the company will combine your search history with data it gets about you from its other products, including YouTube and GooglePlus. To prevent that, see EFF's four-step process here.
Update: EFF is clarifying its advice thusly: "Note that disabling Web History in your Google account will not prevent Google from gathering and storing this information and using it for internal purposes."