My modest technik:

1 - Enjoy it
2 - Think about a basic idea and "chew" it for a while. Discuss it with others
3 - Add a believable challenge to the main character, something to overcome (by far and using megamuscles :-P ).
4 - Intro. Development. Climax. Epilogue or next chapters peek. A very know formula that works with ALL kinds of narrative.
5 - Check if you enjoy reading it.
6 - Make it a surprising INTENSE experience to the reader. (You wont have problem with the intensity It looks like in another month the real you'll be overpowering she-hulk).
7 - MAKE SURE you enjoy reading it.
8 - Write -> Read -> Improve
                   ^           |
                    |           |
                    ----------
9) Release it and then listen (only) to constructive criticism.

Hope it works for you,

CDR