
Peace.
You may see something really groovy happening and happen to have the camera nearby, or you may have an idea--a concept--already in mind. Maybe it's a combination of both.
I went down to the canal with no concept, no real fleshed out idea. Just needed to go out and shoot. I spent about two hours walking around, looking. If something interesting happened--like a heron taking off from a perch--I quickly tried to capture it. (I did! Looks cool, too. Will see it here at a later date.) A couple of bicyclists or joggers headed my way, got them too. Then there was the shot you see (sort of) below. I found myself standing there watching the water rush by, listening to the birds, the wind in the trees... taking it all in.
In one direction I noticed an interesting possibility for a shot. Bringing the camera to my eye, I began looking for just the right composition. Moved a little to the left, then right, then up a little, walked forward.... Without tripping the shutter I kept moving around until it felt just right. When it finally did (sometimes it never does!) I took a shot and examined it on the LCD screen. Looked good there, too... but it needed the human element. I put the camera on the tripod, recomposed the shot and pre-focused to a spot down the towpath a ways. Then I waited. It was still a little early so foot traffic was still light. I decided to set the timer and at least get a self-portrait. Ultimately, people did ride, walk, run by in each direction. Got a few images to choose from and will probably go back for more... maybe bring a model just in case!
In the mean time, here's a double self-portrait.
In fact, in the '50s and '60s National Geographic photographers often carried with them red scarves or shirts for use when the color didn't happen to be around "naturally." (That practice, today, is frowned upon but likely not strictly enforced... if you know what I mean!)
Every now and then you do get lucky, though. I was making my rounds down at the canal yesterday when in the distance I saw this fellow on a bike headed my way. I quickly got myself into position, composed the shot, then waited for him to enter the scene.

Looking at it now, I think I should have laid flat on the ground. This would have eliminated the light brown path he's riding on. It's a bit of a distraction I think. Ah well, next time!
Cheers.