I've been looking at the photos of everyone who's posted here who has something accessible. From that, and from what goes on in my mind when I'm taking pictures, here's what I think/do before I press the button, that I think other people should also do, no matter what style of photography they're doing:
1/ That's a great setup but is it just a cheap visual pun or cliche? If it is, skip it--don't get too invested in your own cleverness.
2/ Will anyone else find anything in this picture, or does it depend too much on having been there, either physically or more importantly, emotionally? (Not a big one if other good-photo rules get followed, as always--hopefully these just get edited out later when you can't remember why you shot them or don't think anyone else would care; but too many Flickr pages are filled with 20 almost-identical pix of your kid or your dog or your cat, etc. where one, or better yet, none, would have been enough).
3/ Is there a better place to stand to pack it all closer together so that it makes a stronger point? Notice that movies are almost always shot with people standing much closer than they would be in real life--that makes everything clearer and more intense. While you're at it, is there some way to clean up that background full of irrelevant clutter?
4/ How much closer can I stand before important things get cut off? One of my students told me once that a previous teacher had said frame the shot, and then take one big step closer, and that's not a bad idea. Just putting something off center to put it off center does not a great photo make; it needs a reason to be off center, or it's just a waste of good space. It's especially irritating if there's too much space in one place, yet something important has been cut off elsewhere (one person's Flickr stuff here has that problem way too much). Frame so that it would be impossible for someone to come along later and crop your picture without ruining it.
5/ For god's sake, try to keep your camera level. If that's not what you want, tilt it more to make that totally clear.
6/ "Pretty" is not enough reason. Not ever.
7/ Try to develop a style.
This guy got hammered by the critics not because of his skill, but because (due to his family history) he was being exhibited while he still didn't know what style of painter he was, so each painting looked like it was done by a different person.
For myself, I've come to realize that I don't like pictures that objectify people. I never really understood what women meant when they said they felt objectified, until I thought about it in my photos. At this point, I don't believe in using people as props, then. That pretty much limits me to people I know, or at least have met and know something about. The best thing about being a newspaper photographer was having the excuse to walk up to people whose picture I wanted to take and introduce myself, talk to them about what they were doing, and then make some sort of photo that communicated something about who they were and what they were doing. It gave me a constant flow of subjects, people to meet, know something about, and then, finally, photograph in a way that was personal and relevant to that individual. Consequently, "street" photography has never held the slightest amount of interest for me, not doing it, nor looking at it. Far too many street photos violate point one, above, and often the others, too. I'm a big HCB fan, but mostly of his portraits. Notice that when he quit, it was portraits that he kept doing.