Decoupage is one of those crafts where the finished product is sometimes deceptive. Depending on what you make, the finished product can be so stunning that it appears to be professionally painted. By looking at the finished product, you would think decoupage would be complicated, but it isn't.
Decoupage is actually quite simple! If you can cut and paste, you already know most of the techniques involved. Basically, you cut out pictures; you glue the pictures onto an object; and then cover the object and pictures with a few coats of glue/decoupage medium to protect it.
Of course, you can buy supplies and other items that are made specifically for decoupage. One of the nice things about this craft, however, is that you can also use supplies that you probably have laying around the house right now.
Now, start gathering those supplies....