Also, this project allows for tons of creative freedom, so you don't have to make it the same way I do. I made these specifically for a Silent Hill nurse costume, so I made them a bit more claw-like by cutting the sides of the nails at an angle. That isn't necessary if you don't like the way it looks.
Step 1: Everything you'll need!
Next, you're going to need some acrylic paint in dark green, brown, black, and (optional) white. You can get these at any craft store for pretty cheap.
Scissors and an emery board are also going to be pretty necessary. (the emery board is included in this nail kit)
Lastly, a basic paint brush, something to wipe excess paint on, and something to mix colors on.
A few other optional things you can use are some newspaper to paint over to avoid a mess, some water to clean the brush, gloves to keep the mess off your hands, and acetone to remove any excess nail glue from your skin.