I took full advantage of winter break at my parents' house. They have a spacious garage chock full of every tool imaginable, and I was in heaven. I took the dogs out for a walk to the park one afternoon and found a couple perfect branches, so I couldn't pass up the opportunity to make these darling little buttons!
Begin by using a sharp tool or a pencil to mark the intervals where your buttons will be cut. You want them to be relatively thin, but they should not be so thin that they risk snapping. I found that they should be at least 1/8" thick. I marked next to my notches in yellow so that you can see them more clearly.
Cut the end of the branch using the hacksaw or electric table saw. The project is admittedly far more tedious when sawing by hand, but I wanted to show that this could be done without any major tool investment. If you do have an electric saw, I would recommend using that for expediency. Of course watch your fingers, and wear your safety glasses!
Using your drill or Dremel with a very fine drill bit, carefully position your bit just left of center and drill through the button. I drilled atop an old piece of wood to protect my work surface. Repeat with the other side of the button to create two holes for sewing. If you prefer the look, then you can drill four holes instead.
After sanding, simply polish each button on both sides with a wood product, such as furniture polish or the like. This will seal the buttons a bit and give them a more 'finished' look. I used Murphy Oil Soap on mine because it was all I had on hand, but it's really more to clean than polish. I'd recommend a polish or wax for this step.