Write!!! You saw that coming huh? It's obvious but often overlooked, writers should write everyday, period. Write in a little notebook, take notes on your phone notepad, do a blog!!! But give yourself a project along with a moment or two to express yourself and to dive into the images in your head. Lay down some bullet points about what you're seeing, and most important,.. what you're feeling.
Most of us have the image of writing as if we're supposed to be sitting at a big desk in a library with quill in hand. Truth is sometimes it's a quick paragraph or half sentence your imagination captured and scribbled down on a napkin or posted note!
As a comedy writer your writing may lean towards the 'inconsistencies or defects' in your life or the world around you. That kinda comes with the territory of standup comedy, eh?...we're constantly talking about those two things. The world (thank god for writing jokes sake) is FILLED with inconsistencies and defects to question and shed light on. Tell yourself you're going to write a personal 'joke of the day'. Just one!!! You will do it!!
Remember that writing is re-writing. If you don't feel you have anything fresh go back over some old notes or in the case of standup, old bits or jokes....add tags and/or expand the thoughts. If you do this you'll soon hit some fertile soil to begin again fresh.
Sometimes you can fool yourself into writing by using 'down time' to take your thinking deeper into your subjects and feelings. Don't even call it writing time, just thinking time will do. Make some notes only. Now that's writing!!! Also consider there's nothing like a deadline to help you write, so give yourself one by making a commitment to write something every single day. It will surprise you how a few what seems to be disjointed things you've scratched down here and there during the day can come together with a later overview.
Write or re-write everyday, but for goodness sake....just write, DAILY! Now go be funny! peace