Excellent advice and I completely agree. That said, I find sometimes, especially in certain Facebook groups, that I'm very hesitant to give feedback even if it's requested. I have done so on occasion, and always privately and I do know how to give constructive criticism. I'm very specific and I do teh "sandwhich thing," point out the good, get into the areas of improvement and then another good. Some people are genuinely happy for the feedback. Others, well, they really don't want feedback, they want a read, and don't take the feedback well.

I've given up on giving feedback unless the writer is someone I am familiar enough with to know that when they ask for it, they actually want it.