I reached into the vault and took some pics of custom minifigs I had made as a child using various things such as:
Little hand cut pieces of vinyl stickers in various colors
an exacto knife
super glue
sharpies
tape
thin sheets of white plastic
rarely paint
:)
Here is Link: Idk what happened to his hat or sword.

My dark Sith starwars guy that I was super proud of:

NINJA JIRUE (Before and After I did mods)

FYI: That is how I got my name. The name i chose for my little ninja minifig who would one day fight evil in an animated short that I never made
Here's a pic of his holster that took me all day using an arrow quiver and a closeup on the paint job on his sword

and his ARCH NEMESIS: SHADOW

These are the coolest ones I could find when just digging through my bin of minifigs. I made these in late elementary school-early middle school