Self cut techniques

Yes self cutting is the devil and all my hair will fall out l.... If your thinking that you can excuse yourself now.

Anyway I have been cutting my hair myself for about two years now (can't afford it and they messed it up half the time anyway) I have long wavy hair that has a small strip on top that is very curly and frizzy. I have been using the ponytail method to get long soft layers but im noticing that my hair is longer on the sides than the middle, I know thats because of how I'm cutting it so anyone have any othe techniques that would keep that from happening?

"Get a professional hair cut" is not a technique