Choice of search engine is another item which helps protect your privacy. Both Google and Bing keeps a log of everything you search for and uses it to improve search results and provide information to the government when requested.
Google https://history.google.com/history/
Bing https://www.bing.com/profile/history
Yahoo (A bing proxy) https://search.yahoo.com/history
Ask doesn't provide you with a way to see or delete history, they do collect this info though.
In order to provide better privacy, you have to use a proxy site. These proxy sites would search on your behalf and not keep logs of what you search for or when you search. This protects you when you search for "How to build a bomb" and don't want to get caught ;).
Proxy Search Sites I recommend are:
https://github.com/asciimoo/searx
This is the one I personally use, it is open source, secured with SSL properly, and provides many preferences to customize which search engines you want enabled. My personal settings is DuckDuckGo and Google as the search engines. One thing I never understood is why they default to Google and 3 Bing search engines (Bing, Yahoo, and DDG).
This search engine is the most popular proxy search engine out there. There is two issue I have with it and that is it's a proxy for Bing and other search engines (https://duck.co/help/results/sources/) which doesn't give me the search results I want being a programmer and also DDG is not open source, so I can't see how they work.
This is a Google search proxy which is similar to DDG. the only thing I have against it is it's not open source.
Everything is up to you on what you want to use. I may eventually write my own search proxy in go because go is my favorite language. I had a search proxy before, and I even attempted to make my own search engine which crawled the interwebs, but quickly found that I failed quickly at it. There is a reason these search companies has multiple gigabit connections and lots of servers.