A plan is nice, but if you get an idea, sometimes wingin' it turn out some really nice surprises.

I usually get an idea, try it, realize it isn't working out (cause my ideas are usually better than my skills), then start tweaking, zooming, panning, adding, removing, etc...

Sometimes it works out...sometimes, yuk.  I have a lot of never rendered pz3's on my computer.  Great idea, poor execution.

Always fun to try, though!