Start by looking at the non-Windows ones. If you see something familiar like Adobe Flash Player Updater, or jusched.exe (Java Update Scheduler), go to the control panel of said program and disable automatic updates. Also right click the Window Start Menu icon in the lower left corner and choose Programs and Features. Uninstall every program you really don't need, including the Windows apps you never use. Unfortunately there's some features you aren't allowed to remove any more, at least not easily. Let's hope they don't interfere too much. You may have to do it several times until everything is gone. Some of them may even reappear after updates, so keep that location in mind for future cleaning.
Now that you're in the Settings, go through every title and subtitle. There's a lot of things in various places with a slider set to enabled. Many of them ask if they can gather and send information about you for marketing purposes. Well, they actually say they want to enhance your experience, but all they really want is your money. Disable them!
For further options to tame your Windows,
www.blackviper.com is a good source of information.