Ombre can be a little tricky to do, but when done correctly, it can look pretty darn cool.
Grab some paint, water, a sponge, and get started.
Use the water to dilute the paint as you get closer to the area where you are going to introduce the next color.
The sponge is a great tool because it makes blending way easier than if you use a paintbrush.
Once again, use that Modge Podge to keep everything in its place.