Writing buddies are awesome. You don't have to keep it to just one - maybe two or three, but I wouldn't go more than that. They're great for bouncing ideas off of, encouraging, keeping each other accountable and motivated, all sorts of things! Just make sure you find one that will be honest with you and tell you if your ideas are bleh, or if they have potential.

Sharing with a large group works great sometimes, and sometimes you need a smaller more personal conversation. Don't be afraid to jump in and ask people. They don't have to be writing the same kind of book as you, they don't have to be the same age, they don't have to be the same gender, be in the same state, be the same age... they just have to be someone you trust that will encourage and be honest with you, and you are willing to take feedback from.