Type whatever you want.
Cmd-b
Your default web browser with your default search engine will now open and perform your query. I can't stress this enough how much I use this workflow when writing code.
Another thing for the OPs issue with the screenshots, (there's a few steps via terminal so maybe try the above shortcut to search for an article on how to do it) you can have all your screenshots redirect to a folder.
For example all of my screenshots end up in $HOME/screenshots
Also, another cool and sometimes useful shortcut, holding option while clicking is a big thing in osx. Try click the wifi icon in the top right corner whilst holding the option key. It will give you a bunch more details :)