Writing stand up comedy is probably the most difficult part of this whole process. Performing, memorizing and editing material is much easier once material exists. Creativity is a core issue for stand up comedy. Comedians that use "easy" material to get results are considered hacks. In order to maintain respect amongst comedians and audiences, it is important to develop original, innovative and consistently fresh material.
This is so difficult. 
I sat in a coffee shop and kept my pen moving--one of the best cures for writer's block. No matter how dumb my jokes were I kept the pen moving. 
More than stories, I focused a bit on one liners today. One liners are great for openings, breaking the ice and building momentum. Many of the one liners I wrote are pretty bad, but I think some can work.
Here's a bad one I wrote:
When people tell me that I count, I tell them I can spell too.
Who knows what jokes work with a live audience. I sure don't. I want to get some of these in my arsenal for quick laughs and building upon small victories.