I started out with a plain cardstock (the brown) and cut it into a square shape that would fit inside my envelopes. Then, I put a patterned paper (blue stripe) in a slightly smaller square on tip. I finished with a lighter brown paper that had all of the invitation details on it.
For a little more detail, I used a pen to draw a line around the edge of each different layer and I used some brown ink on the smallest square (the one with the printing on it) to help it stand out a bit. Then, I glued a bunch of cute buttons on the bottom.
For the ribbon on the top, I used an Exacto knife to cut two small slits on the top and then pulled the ribbon through.