Multimeters seem simple enough to use. You turn it on, connect the leads, then start poking things. Really though, there's a quite a bit going on in a multimeter and a lot of different settings to get used to. Make has a guide that walks you through everything you need to know.
Photo by Becky Stern.
Make's guide covers everything from the initial set up to choosing the right range, values, and checking continuity. They teach you all this through a few different practical procedures, so you're not just learning a ton of terms at once with no practice.
If you're new to electronics tinkering or you just need to use a multimeter now and again, head over to Make for a great starter guide.