Your smart phone is providing tracking information to companies. But then what do you care? I've nothing to hide!
It's curious that many people would be adverse to government surveillance. Remember 1984? But if it's a company, meh... As a reminder I would like to point out that although surveillance is bad, at least if it's the government, the people have the possibility to change those practices through judicial, electoral or political procedures. And let's not forget that the companies in most cases are providing surveillance information to the government and security apparatuses.
It is impertinent that one be very aware of what information your phone may be directly providing or that can be inferred from your phone.
As noted in the "On the road" section, various connectivity services (Wifi, Bluetooth, NFC) can transmit information about your whereabouts. That's what I mean by inferred information.
However, as we expect our phones are also providing the telcoms, and various companies directly information about your location, etc. Be sure to disable all location, microphone, video and other privileges any apps may have. At the very least allow an app to have access only when that application is active. Nonetheless, if the app has trackers, I would advise always putting that app in paused mode, so they are completely inactive.
The "Mobile" section also has a lot of information to help you curtail various tracking apps on your phone.