This is a simple one but it took me a while to discover it.
When you are on a website and want to access another through a link, but you don't want to lose the page you're on, right click on the link and choose 'Open link in new tab' (or window). Most sites now do this automatically and this one didn't until I stumbled upon how when looking for something else..
Here, try it on this one: http://www.monologues.co.uk/
And have a butcher's at the site while you're there because it's wonderful.