Some people don't plot. I don't, but I try to keep track of what's going to happen next.
My ideas always begin as summaries of a story, usually 500-1000 words, and then I keep notes below my writing that list key events coming up.
I don't know if anyone else does it like that, but if you like to plot out your novel, there's a lot of different methods instead of just a straightforward plot/outline, so find what works for you...
The Three Act Structure
Speed Outlining - Ten Point Outline
...yes, I am too tired to rant lately ;)