Put The Comma, Where?

I have a comma problem. Not a common problem. A comma problem. I was watching the show "Lie To Me" the other night, (The one where "Dr. Lightman" can read people's facial expressions and know if they are telling the truth or not. Love it!) and on the show, Dr. Lightman has been trying to write a book. He has a semicolon problem. He likes them, over uses them and puts them in places they shouldn't be. I have a comma problem. I tend to write run on sentences and then I need to insert commas, but I am not always sure where they should go. So, I put them everywhere. If you look back at the last sentence, I am not sure if the comma should have gone after the word "commas," or after the word," but." I am not even sure if that last sentence was correctly comma'ed. (Is that even a word?) I need to refresh my English class skills. I suppose I could look it up on line and figure it out, but I don't want to. So, as you are reading my posts, I apologize for all the comma mistakes. When I hit the lottery, I'll have my editor take care of it.