Being my first painting, I assumed this could go horribly wrong but I asked as many artsy fartsy people for advice as I could and it turned out great. This is why I know you could do it too!
First get yourself a canvas and put down a base coat of choice. I actually used wall paint for mine. I have so many samples of paint from my various projects so I went cheap and picked one of those. I rolled it on with a roller, make sure to get the sides too. I did two coats to be sure since canvas is very textured and porous.
Next, pick out colors from your local craft store. I used small bottles of acrylic paint. They should have empty bottles for cheap too, you will need one for each color you buy.
TIP: It really depends on the look you're going for here but I learned from trial and error, it's best to buy colors that are in a really close range to each other. Some of the darker shades and more pastel like hues ended up sticking out like a sore thumb. I also started out with about 4 colors and ended up going back for about 4 more to get the color range just right. But again, this is really personal preference.
After your canvas is dry, lean it against something with a tarp underneath, things are about to get crazy. Empty out about 1/3 of the paint into one of your empty bottles and add about 1/4 of water and shake. You may have to play with your amounts here. On some shades I found I needed more or less water.
Then turn the bottle over and start running it along the top of the canvas as desired. For longer drips you will need to hold the bottle in place and squeeze out more paint. If you want to stop your drips at certain levels just lay the canvas down for a bit.
Then I just started randomly placing different colors here and there. This is where it got a bit tricky, some colors started to run together a bit or began dripping down the same "trail". Basically this means that you need drying time in between layers. I wanted mine to have a lot of layers, again personal preference. So I did several sessions over a few days after work.
Then when you're happy with the amount of colors/layers/textures you're done! It's really up to you.
I'm possibly considering doing a different look for another room by rotating the canvas as I go. The good thing about this is there's so many options and if you get a drip you don't like or gets messed up you can cover it up with another color. It's pretty hard to screw it up and that's what is so awesome about it!
If anyone ends up doing this PLEASE send pics! I would love to see what variations you guys come up with!