I have a sister. I was born having mine. If you weren't born having one, and your parents never provided one, then you need to go find one, especially if you really want to be a good writer. This can't be just any sister. She has to be like the one I have.
First of all, she has to be voracious reader. It helps if she reads everything from Clive Cussler to Nora Roberts. It's imperative that she be willing to close a book after fifty or seventy five pages or more and say, "This isn't worth my time. There are just too many really great books in the world to spend time reading poorly written junk." If she can do that, you know she'll recognize talent—if you've got any.
The second requirement is patience. If you want your sister to be your first reader, then she has to realize that she's only going to be getting a couple of chapters at a time. Even at the pace I'm writing, that means she's only going to get a couple of chapters every other day. That's a very slow way to read a novel.
The third thing that I would consider a necessity is honesty. She can't love you so much that she can't tell you what she really thinks. Tonight for the first time Ellen called and asked me if I wanted constructive criticism.
"Yes," I said.
"Well, I don't have any. Write faster!"
The bottom line here is that what every writer needs isn't just a sister. It's my sister. She encourages me. She gives me confidence when I'm afraid the story will get stopped up in my brain. She lets me know that somebody besides me will see value in it.
She's my sister. You can't have her. She's mine. I need her. And I love her. Thank you, Ellen.