There have been a couple discussion posts on this, but let's make it general and collect our tips in one place. It's also a good way to encourage each other at getting better at this - looking for info more often and more efficiently.
So, if you want to find something out, where do you look, and how? Who do you ask?
Keyword searches are extremely useful.
I make excessive use of these, I can just type "i birch" in the address bar and get a google image search for "birch"
My keywoard searches include:
How do you create keyword searches?
In Firefox, it's explained here : http://robertnyman.com/2006/09/13/smart-keywords-in-firefox-are-outstanding/
In Chrome, it's explained here: http://lifehacker.com/5476033/how-to-set-keyword-bookmarks-in-google-chrome
In both cases, it boils down do associating a keyword with a search url of the form "http://en.wikipedia.org/w/index.php?search=%s&title=Special%3ASearch", such that when you type "keyword whatever" in your search bar, %s in your search url is replaced by 'whatever'.
Combine this with the fact that adding "site:somewhere.com" in a google query restricts the search to that domain, you can make custom searches for any website (though in some cases, like wikipedia and stack overflow, the site's search function is more useful - for example, that wikipedia query up there will bring you directly to the page if it exists).
It's worth noting that there is also DuckDuckGo (a search engine), which has bang expressions for outsourcing results. Just to give some of the equivalents for those listed above: "!gi" for Google Images, "!yt" for YouTube, "!w" for Wikipedia, etc. To be sure, one has to rely on DuckDuckGo for adding the expressions (although I've had success suggesting a new expression before).