Suggestions for a misbehaving 4yr old.?

We have a 4yr old little girl and her behavior is out of control.We have tried ,timeout,ignoring,talking calm to her.but what else can be done.She screams,doesn't listen when we tell her no,she does things very spontaneously and when we try to teach her something she won't sit and learn.I have nearly ruined our marriage over this and need some advice.