A simple, effective way to improve most compositions is to crop (or zoom) more tightly. Cut out the "distractions", and boom, powerful composition. I usually shoot with a slightly-long lens in the normal range, or with a short portrait telephoto, so this is basically automatic (whether I want it or not).
However, it's sometimes nice to have context. Sometimes, you want more of the story, and by leaving in the "distractions", you provide more of the truth, less selective tunnel vision.
So, I picked up the Pentax smc DA 15mm f/4 ED AL Limited , which I've been coveting for a while away. This is an "ultra-wide" lens even on my APS-C DSLR. But, it turns out to be, well, hard. It's not just a matter of making sure my shadow isn't in the frame; it's hard to get all of the elements to pull together in a way that add up to anything.
Photo by me, hereby released to the public domain on account of being boring
If you have something extreme like a Lensbaby Scout with Fisheye optic, it's a lot easier to be interesting:
Photo by me; CC-BY-SA 3.0 in this size
I mean, really, that's like shooting fish in a barrel. (Um, no pun intended.)
One can do similar (but a bit more tame) "extreme perspective" shots with the DA 15mm, since it has a close-focus working distance of about 9.5". However, that gets a little tired and gimmicky after a while. The whole point of adding to my lens lineup is to expand my horizons (both literally and figuratively), not to give me an occasional gimmick to pull out when I get bored.
The Lensbaby Fisheye was really entertaining to use, and the Scout is a gorgeous piece of hardware, but I couldn't really justify the price for its narrow (for me) application. The DA 15mm Limited gives me something that I'm hoping will be a more practical member of my camera bag, but it's clearly going to take some effort and practice.
So, how can I consistently make wide-angle photos that work, of a variety of subjects? I want to work towards pictures with context and story, not simply close-up images with perspective distortion.