This was my inspiration - a pin I made for Canada Day a couple of years ago. This pin is waaaaay too big, almost 5-1/2" across, so I took it apart and made a smaller version.
Using the same technique, I made a shamrock pin for St. Paddy's Day. I could have looked on Google images for "line drawing shamrock" to get the shape and size I wanted for a pattern. But then I found some shamrock stickers at the dollar store, which I used as the front of the pin and for a pattern for the stabilizer and backing. Here are the supplies:
Sorry about the glare on the package of stickers.... From the left, a package of sparkly fun foam stickers from the dollar store; a bunch of buttons; several kinds of beads/sequins; black Peltex, a very firm stabilizer; a sew-on brooch back; green wool felt; embroidery thread. IMNTBHO (In my never-to-be-humble opinion), wool felt is the only kind of felt to use. So nice to work with, such beautiful rich colors, and much better coverage than thin and scratchy "craft felt". I buy wool felt squares at www.joggles.com , which is also an excellent source for beads, threads, and other goodies. Joggles has inexpensive and fast shipping, high-quality products, and very helpful people. Be sure to check out their online tutorials, for dozens of techniques and projects.
To make the pin, I put a sticker on the Peltex, using it as a pattern. Then I trimmed down the stabilizer, so the black wouldn't show through to the front of the pin. You can see that the glitter from the sticker migrated to the backing; and yes; it was all over my work surface, hands, clothes...
Then keeping the Peltex and the sticker as one unit, I stitched on buttons, applying the biggest ones first and filling in with smaller buttons and finally beads. Buttons with shanks are good to fill in small gaps, as only the shank needs to fit in the gap, and the button face sits on top. Because my base is a sparkly sticker, I wasn't too concerned about filling in every millimeter of the pin face. With the Peltex adding stiffness and supporting the weight, you could really encrust these pins with multiple layers of embellishments.
Here's the almost-finished pin, just waiting to be assembled.
I used another sticker as a pattern to carefully and exactly cut out green felt for the back. I sewed the bar pin on the felt backing, and glued the units wrong sides together. I used Aleene's Tacky glue, applied lightly with a paintbrush, and used clothespins to clamp it until it dried. This was a fun afternoon project, and I wore the pin on a blazer to church yesterday. It made a couple of people smile, but especially me!