If you're not signed in
If you're not signed into your Google Account when you visit https://www.google.com/settings/ads, you'll land in the area where you control what happens to your information off of Google's sites and in Google Search.
This is a good reminder that even if you aren't signed in to a Google account, Google still records what you search for on Google Search and builds an interests list using cookies stored on your computer. The upside is that it can't link your information to a name, but Google is still tracking your interests and using them for ads.
This is also a good time to point out an ad feature Google has called "Customer Match." It allows advertisers to send you targeted ads based on your email address in their records. Facebook does something similar.
For example, if you use your Gmail address to create an account on a shopping site, the site can submit your address to Google. When you're signed in to Google, Gmail or YouTube with that email address, Google will show you ads from that advertiser.
However, the place to disable this is on the page that controls what you see when you're signed out of Google. So, let's take a look at those options.