I think its important to work with readers/proofers that don't cramp your style.
1. Most of my proofers/editors/critique masters volunteer themselves. I think this is important. Rather than it being an imposition, these people genuinely want to read my work and help.
2. They should have some interest in fiction.
My boyfriend Scott doesn't like reading fiction or talking about things that aren't real. But despite his revulsion towards imagination land he has helped me develop some crucial concepts for my YA. Tread carefully with these anti-fiction types, they can give you a good reality check, but at the same time totally stall you're progress with statements like: There's no way that can happen OR You need to show the step by step chemical reaction for that.
3. They should be familiar with your genre.
Most of my pals have read Twilight, Wings, etc... But prior to pal proofing I used to work with a published author, Vicky Covington, on my manuscripts. Vicky is AMAZING. She literally taught me to some extent the craft of writing. She taught me the importance of Less is More; Showing rather than telling; and Just getting the damn thing on the paper. She helped me with my first novel, an adult women's piece, that I will never pursue to publish, but still learned a tremendous amount from writing. But, when I proposed my science fiction YA to her, she crinkled her brow, and I could tell off the bat she wasn't in to it, and that's when we went our separate ways. And that's OK. I think it's really important to surround yourself with people who get your vibe.
4. You need to work with people who won't get offended if you don't take their advice.
I love it when people critique my work; when they point out grammatical flaws (commas are a mystery to me and I always use its and it's incorrectly); or when people pose questions or problems with the plot or characters that I didn't think of. But, on the same token, it's your work, and you get the final say.
How do you guys feel about friends and family critiquing your work?