My creative process is 90% mental and about 10% physical. I spend quite a lot of time with an idea "percolating" in my head - sometimes weeks or even months. I think through characters and stories to make them plausible before I ever get them out on paper. My partner also helps me out with this process. I take him to lunch and start throwing ideas at him - he is often times able to polish an idea from the reader's perspective and give it back to me ready to write. For a novel or short story I usually have a good idea of how it starts and how it ends, but the middle is the fun part and I let my imagination run when I'm fleshing out the story.