Plastic buttons (Or more accurately, buttons with plastic holes)
Earring posts (I like surgical steel, but I buy in bulk)
1. Take your earrings off the paper backer and use your pliers to remove the hole. Sometimes they are just glue on and pop right off but other times they are PART of the button and need to be bent, tugged, twisted, and pried off. If the latter was the case for your buttons, follow up with sandpaper to sand the back down. No sandpaper? No problem, go outside and use the side walk. Seriously, that's what I do.
Done. Really, that is it. See some of the earrings I made below - I took less than an hour to make all three pairs.