.Writer's block usually occurs when you are trying to write jokes for your standup that sound funny on paper and that you think will sound funny to an audience. If you remember a simple fact that your jokes are 'created' not necessarily written out longhand, you will NEVER get writer's block.
By created I mean that you look for images of topics you want to cover and then simply list the bullet point emotional words, phrases, ideas that cover that image or situation, you shouldn't run out of things to write down. When you take it to the stage you allow your personal communication skills to take over and add the necessary words to 'workout' the idea. This way it comes out in YOUR voice and with YOUR attitudes and bada bing you're on your way to having a comedy bit that sounds like you along with your comedic character and without ever the slightest snag of a writing block.
Because remember!!! If you want to be successful.
YOU CREATE FOR YOUR STANDUP.. YOU DON'T WRITE JOKES!!!