Spend more time.
The top movies in the portal all took way over 2 hours. Try 2 weeks at the very least. Some advice is to learn how to manage your layers. It's good that you're able to tween and make a walk cycle (which could use lots of improvement) but there's much more to great Flash movies than those two factors.
All you need to do is spend more time using the program. Resist the temptation to submit every piece of work that took longer than 10 minutes.