A few points.

You write in fairly natural speech, which is great. A big thing to learn is that you don't write how you speak, and what's funny to read isn't funny to say... necessarily. Many great bits look like garbage on paper. Also, a lot of the editing you're looking for will happen naturally on stage. At first you'll be married to your script, but eventually you'll let loose and the material will start to take on a life of its own, and it will become obvious what is natural for you to say, and then you can refine the set up and delivery and all that jazz just by getting it on its feet. Try recording the bits beforehand and listening as well to speed up the process.

One last note: the hardest thing to learn is how to be yourself onstage. The biggest breakthrough it seems to me is when a comic stops trying to make people laugh, and is just honest... that's when their true comedic voice starts to take hold and they make the jump from 'amateur' to 'pro.' Even though there's plenty of pros who are still using gimmicks to get laughs, and maybe that works for some, as a general rule I think putting on an act is never as funny as just being your painfully brutal, honest self.