I tried making holes with a fid l I got at Tandy. It worked for a while, but I often had to sharpen it. I went back and got a diamond shaped awl, and it works great. I haven't sharpened it, and have used it a lot. I mark my holse with a overstitch wheel. If you bear down on it and run it back and forth, it will make visible marks. Then I punch each hole with a rubber hammer and a diamond shaped awl while the holster lays on a pine board. This works well for me, and if you turn all the diamonds the same way, it is quite attractive.
I burnish with Gum Traganth and a deer antler.