I started with my bed, which is dark wood. First, you have to dismantle it. Then you need to sand it really well.
This is a close-up of just how well you need to sand it. It should be really scratched up. When you're done sanding it, you need to wipe it down with a wet cloth to remove all the dust.
Once you've sanded it, you need to prime it. Because I'm trying to be as green as possible (like buying only secondhand furniture), I used the primer we already had in the house.
It was kind of a bad idea, because I had to brush it on, which is not ideal for a bed like this. If your furniture has less detail than this, paint primer works fine.
Because my bed is so dark, I needed two coats. If you were redoing a lighter wood, you might not need two coats. In fact, if the original wood is very light and the color you're painting it is darker, you might not need primer. It's all a matter of dark to light. The flourescent pink I used didn't look right without the primer.
Now, it's time to paint. I chose spray paint, because regular paint doesn't come in flourescent pink. If your furniture choice is as detailed as mine, spray paint is still the best option.
It is best to spray paint in a basement, garage, or outside. It is best to prop up the item you're painting, so you're painting it directly in front of you and not pointing down.
I was restricted and unable to do this.
You should also put drop cloths on EVERYTHING. Spray paint leaves a very fine dust that will get all over everything. EVERYTHING.
When using spray paint, you need to spray in very thin, even coats. Don't worry about covering in one coat, 'cause it won't work. If you spray too much, it will get all drippy. Keep the can moving and spray in light, even coats. Each coat dries in about 15 minutes, so it won't take long to make the three coats you'll need.
Now that you're done, once everything is dry, assemble and take a picture of your awesome new bed!