My main objective in taking a picture for making a waymark is to follow the rules. Secondarily, I like to get a shot that isn't ruined by something like bad reflections, shooting into the sun, shooting from my car window and getting part of the car in the shot, etc. My third priority is to get my picture taken without calling undue attention to myself, perhaps a weakness on my part. Certainly, if I can see how to get an extra nice shot, I will go for it.
I always check my pictures before uploading them. I crop them if there is too much extraneous stuff in the picture like too much sky or asphalt. (There is something funny about the waymarking site's thumbnail versions - any cropped picture shows up as a thin line in a black rectangle, but the large view is OK. Or is it the editor I'm using?)
Another part of checking a picture is to remove/blur personal stuff - licence plate numbers and people's faces. Distant faces in a crowd are OK, but a picture of an antique store (I waymark that category) with one person sitting on the bench outside psychologically makes it a picture of that person, not the store. I spend time editing a picture if I think it needs it. I blur out licence plates and possibly bumper stickers if I wasn't able to avoid them in the shot. I use a photo editor - I think they all have a blurring tool. In one incident, someone was selling their paintings in front of the store. I didn't want to be uploading their paintings to the internet and there was no other way to get a shot that followed the rules. I blanked out all the paintings by copying adjacent pieces of the store's wall onto them, and blanked out the person selling them as well.
As an officer, I avoid the swelled-head syndrome and never reject a waymark submission because of some photo quality issue I may have with it. If it follows the rules, then it's in. Avoiding subjective rules like "it must be a really good picture" is part of the nature of waymarking, I think.