I actually did these pants a couple years ago because I've had these pants since Jr. High and haven't worn them since.
An old pair of pants or pants you don't wear, works/looks better if they're a light wash
Paint, any color (keep in mind, water color is more likely to wash out so acrylic or tempura might be the best)
Ink (black would be the best to stand out against the light wash and the paint. Since it's a little expensive, I listed it under optional. You can just substitute black paint with this)
Step 1: Roll pant legs up to desired length
Step 2: Splatter paint wherever desired
Step 3: Using a Q-Tip or your finger, paint a word on it (optional)
Step 4: Wear your new creation!