I cut my hair today. For me, a pedestrian event, but most people get really excited (or nervous) when I say that I cut my hair.
It started in 5th grade. Yes, I've experimented with cutting my own hair since 5th grade, and yes, it went horribly wrong in those formative years. I've had bangs ever since thanks to a stupid hair cutting decision when I was 11. The hair around my face is a bit of a challenge - it curls and bleaches blonde when the rest of my hair is heavy and dark brown. I was done with those hairs, so I just cut them off, at my scalp, at the front of my head - really bad! The hair stylist had to create bangs that rivaled Donald Trump's just to cover up my mini buzz. You would think that would have cured me from ever taking scissors to my hair again.
But no, in high school, I sported the lovely feather bangs of the late 90's. Right before a formal, I cut them, too short and uneven. Again, totally mortified. It never occurred to me to just use bobby pins to pull them back for a little while.
Now, I cut my hair all the time. In fact, I haven't been to a hair dresser in over 2 years. My hair grows very fast and has some highly unruly spots, so the conventional "this works with thick hair" attitude doesn't work for me. Also, the $30 a month, doesn't work for me. So I bought a decent pair of scissors, talked to my sister (who has cut her own hair since middle school) and went to town.
To cut your hair:
1. DON'T!!! If you don't care about how your hair looks (you won't take the time to become proficient with the scissors or study your hair). If you have no idea what works with your hair (the whole point is to cut it exactly how your hair works best). If you can't handle some stray ends that have to be cleaned up later. If you have really straight, unforgiving hair (as long as my hair has a lot of layers, you can't really tell what's going on).
2. Find a quiet time - i.e. when babies are napping and kiddos are out of the house.
3. Wash and comb (not brush!) your hair
4. Cutting the length - this takes some trial and error, so start long. Sarah (my sister) and I have both given ourselves bobs, when we were really going for shoulder length. Sarah starts by putting her hair in a high pony tail, flipping her head upside down and cutting the pony tail straight - this creates instant layers as well. I tend to cut everything straight (does require two mirrors) first, then layer the fool out of it.
5. Adding layers - Start near the front (I start on the left because it's easiest for me). Comb out a medium vertical section of hair (the hair covering your scalp from part to 1/2" above nape and about 1/2" front to back). Hold between your index and third (driving) finger. Pull the strands up so that the bottom strands are furthest from your hand and the top is closest. Cut parallel to your fingers.
6. To keep your layers even, always hold a little piece of the section you just cut in with the new section. Work around your head. The more layers you want, the more vertically you hold the section. This will create a lot of variation in length.
7. When cutting bangs, hold the scissors almost parallel to the strands of hair and cut into them. This creates a nice layered effect for your bangs, avoiding the cleopatra look. Also, if your hair has body or curl to it, remember to cut your bangs long. They will bounce up.
What works best for me (and Sarah) is to create a lot of layers in the back and fewer in the front. Also, I don't tend to angle my hair in the front. Like I said, my hair actually curls up front and is straight in the back, so I'm trying to compensate for that.
Good luck! And remember, nothing is more temporary than a bad hair cut or a broken nail.