Can you offer some good advice. I noticed in the "Do it yourself hair" thread, a lot of ladies are trimming their own hair. How do you do it? Or better yet, how do you trim the back? I can see how ladies with almost bra strap do it, but how about those with shoulder length hair or shorter. I went to the salon on Saturday and got a cut, not a trim--with the same layers that I've been trying to grow out. I can't take it anymore--please give me some advice on how to trim shoulder length or shorter.