Two basic tools
If you're going to write stand-up comedy, you're going to need two simple tools - exaggeration and understatement. Actually the second one isn't so simple, but the first one is. Exaggerate everything you can to the extreme, and then double it. Here's Zach Galifianakis - "You know you have a drinking problem when the bartender knows your name. And you've never been to that bar before." On the opposite side of the coin is the understatement. Here you want to reduce something to such an extreme that it becomes comical. If you're going to write one, go for "the understatement of the century." Or as close as possible. The bigger the situation, the bigger the understatement. It is a lot harder than exaggeration, but when the going gets tough, blah, blah, blah. I will leave you with another example by Zach Galifianakis. "I'm an American so its kind of hard for me to talk about 9/11. So whenever somebody brings it up in a conversation, I say "I didn't like 9/11."