I've cut my own hair on and off for most of my adult life, learning to cut it every way from 2" to elbow length. The trickiest part is setting up a pair of mirrors that allow you to easily see the back of your head. I've rigged various setups with hinges and mirror tiles mounted on Masonite, though I can't really give you a good way to do this. Basically, you need one big mirror, like a bathroom mirror, and a place to sit close to it, then figure out a way to support a smaller mirror in front of it to give you a hands-free view of the back of your head. It helps if you can pivot the small mirror or have two small mirrors positioned at different angles.
I've never cared for electric hair cutting gadgets, preferring scissors. Since I've never cut mine super short this works best. I've used short pieces of dowel or short pencils as measurement aides to maintain consistent length while cutting. When scissor cutting, you always want to cut on the outer side of your pinched fingers. And, yes, I have cut myself a few times. Self hair cutting is a skill that takes a good bit of practice.
~ Lyric ~
