I actually did these frames as a birthday present for a friend. You could get creative on what you use for the frame...a block of wood, old cabinet door, etc. I actually have a lot of old wood samples from a furniture company from my work that I used.
So on these wood samples, one had a lot of texture and the other a lot of wax which makes it kind of hard to glue anything on. I had to use a paint stripper to remove the finish from the raised panel in the center.
(If you are going to do this step have a clean surface that nothing can possibly be ruined if it drips our spills.)
(Sorry I didn't get a picture of this)