I have highlighted and dyed my hair since I was in high school. I also used to give myself perms. I can't begin to count the times that I've screwed it up - too light, too dark, too frizzy, too burnt, too orange, even too purple once! In college I highlighted my hair too light and then gave myself a too frizzy perm. I finally bought a hat to cover it up and a boy asked me out because of my cute hat!
I've learned the difference between ash tones and warm tones. I've learned to use drabber (that involved the purple hair in an attempt to correct the too orange). Over the years I've collected a number of hair implements. Here are three, with bristles. I have another one that I may add later...
I used to pay someone to do my hair, but they make mistakes about as often as I do. So, I just do it myself. I've learned through trial and error (and 10:00 PM trips to the drug store). By now I have a whole beauty supply shop in my bathroom and can fix just about anything!