Well i recently took part in Canon photo marathon Singapore competition. Its a challenge whereby we have to accept a theme and then get the photo within 3 hours including downloading to the organising committee's computer before the time limit. Only after which the second theme is released to us till the third theme.
It was a great experience but dull at the same time. My friend and I cracked our brain so hard our brain juice leaked out but that was not all. We just couldn't get a good idea of what to shoot. Many of what we could do was already thought of by the others. We also expected many people to shoot the same things which turned out that way.
Our theme was Passion, Challenge and finally Playtime. Of course within time limits its really a challenge and it was hard to find a picture given that we chose to move on foot as our main transportation.
What we learn was not how to shoot a good photo but in a 'stress' situation, come out with something to shoot. Within a time frame, produce a photo that is sufficiently suited to the theme yet at the same time being able to produce it with available light and composition.
Unlike studio shots or planned shots, many of these are impromptu, much more than street shots. It can basically be anything on top of shooting people.
Though I did not win anything, I think the valuable lesson of pressure actually made me try to do something new. I had a picture that was satisfactory and two others weren't. Well to make up for that, next year....