I am newish here, and just a few personal choices I have made and thoughts I have.
1: Do not expect any feedback on any images.
This is a very busy place, and as such, images, especcially ones which lack that "extra something" may easily be missed. Take this as a hint, "Not the best, keep trying". No feedback for me means I should look at the shot more on my own and try and work out what I feel about it without the feedback from others. Its far too easy to take a few snaps and then upload expecting others to tell you what you should already know.
2: Don't take negative feedback to heart
I am guessing if you are posting an image for comments, you are not simply asking for a "Wow, thats superb!!". If someone doesnt like it for ANY reason, live with it, and take their comments on board IF YOU THINK the comments will help. Never, ever take it personally - if we all like the same photo's, or same styles, the forum would be a very boring place! Learn from all comments, good and bad, and don't slap someone down when they critisize your work, otherwise you will put them off being honest which is unfair for other users.
3: Don't post poor quality shots (relative to what you are capable of)
If you know you can do better, and you know that with a little extra planning and time, that you can improve on the shot, then why post? You already have the feedback you need. Go get that better shot, and only when you are happy with it (and proud of it), should you post it. Then the feedback will be over and above what you already know.
4: It's just a bloody forum!!
People really need to chill out

This can be a real friendly place, and is a great resource (I have learned shedloads in the few weeks I have been using the forum), however, a lot of people read into the various threads etc too deeply. It's a text based forum (well its image based too!!!), however, textual chat is not great for showing emotion, so you should avoid reading into other peoples comments as overly negative or insulting. Water and a ducks back spring to mind, it's just a forum people, and how many of us really know each other?
More to say but I am aware this post is huge so will stop

Gary.