Show her you have failings, don't let her feel that she can't do anything and that you can do everything perfectly. Drop food on the floor, break a plate and don't make a big deal out of it. Let her see that people make mistakes and that it doesn't matter.
Need her help. With stuff you maybe wouldn't normally let her do. Sometimes I let my kids sit on my knee when I put the car in the garage. My dad used to do it with me. Driving at one mile an hour of course!
Let her be a part of the decisions in the house but not so much that she feels all the attention is on her.
Buy the book "How to Talk so Kids Will Listen and Listen So Kids Will Talk". I thought it was mince the first time I looked through it but I really do use lots of the stuff in it, with great success. I now listen differently. When my DD1 is upset I don't try to fix it for her, I try to understand it and the book shows you how to do that. It sounds simple but its really not.
Write her a note. Sometimes I write my DD1 a note to say that I noticed something........ I might write:
"Hi DD1, Just wanted to drop you this note because I forgot to say that I saw you made your bed yesterday. I felt like snuggling into it when I saw it! Is there anything you fancy doing at the weekend? Love you!"
Step 1 is getting the communication going then you can tackle her self-esteem.
My DD1 was not a confident girl at all but she has come on leaps and bounds lately. She is almost 8.