Here are some search techniques that can be used in just about any search engine. They can be especially helpful when the need to narrow or widen search results (too many irrelevant/not enough matches.

"Quotations"- Quotes can be used to find an exact phrase. Say you are searching for a movie named Children in San Francisco. If you just type the name out and search, you may find pages that are about that subject. Or you might find (especially if you are searchin for a less popular/known thing) pages about Children's center in San Francisco, or something else that you're not looking for because many of the words match. If you want the exact phrase to be searched for, type it in quotes and it will find only pages with the words appearing in the exact order without any exceptions.

AND AND can be used to search for something when you want to have each word appear somewhere in the page. The order doesn't matter, but the word has to be there. An example can be children AND books AND frogs. This will give all results with those three words within it, but not necessarily in that order.

OR OR can be useful especially when you're not getting enough results and you can think of a homonym or similarily used word that could be used to replace the one you are using. An example is Children OR kids OR kiddies This will find any page that has one of those three words.

Some internet search engines replace NOT with a minus sign.
Example: 49ers Head Coach -Mariucci

Google uses the minus sign. If you want to exclude a whole string, use quotations also.
Example: "Peter Pan" -"Michael Jackson"