Do: Respond, give tips, criticize, compliment.
Don't: Be over enthusiastic about the criticizing.
Especially Don't: Okay... You know how people on YouTube or Facebook see a video and then have an argument with another user? DON'T YOU DO THAT! I mean, I don't mind if you want to have a conversation with me about how to improve something or "I liked this because blah blah blah" but please don't argue in the comments. I will block you.