Wow I tried reading this and honest to God zoned out. Absorbed nothing. 

I can't actually recall a time I've been given terrible writing advice, but I surround myself with positive people who are all wanting to grow together.

One thing I will say is, regarding critique - I don't think critique can be bad if your intent is from a sincerely good place. Are you critiquing someone to help them improve? Or are you critiquing someone to knock them down a peg? There's a difference. Also are both parties in on it? Sometimes critique isn't asked for and it's okay for someone to say "nah, I don't want your feedback, thank you!"

I actually do a lot of feedback in my roleplays. I've gone through character sheets quite a lot because I can be honest in a productive way that benefits the person who asked for my help, and ultimately helps them a bit in finding what it is they want to say about a character, or in a post. I tend not to focus on grammar and spelling - all of those things are easy fixes, but helping someone to dig a bit deeper to continue a thread or theme is where it's at man. Just round table that in a safe setting and everyone benefits. I would never tell someone "do this, don't do that" only make suggestions, ask them if they've possibly considered a,b,c. Lead the horse to water, but don't force it to drink.