I've talked before about freewriting. It's a process where you select a word, then write about whatever it brings to mind for a full ten minutes. Don't stop and think--just keep writing, whether it makes sense or not.
You can open a book or the dictionary and point to a word to use as your basis for this exercise. Or make a list of words and try one each day.
When you read what you've written, it's possible you'll find some hidden gems. You may have written something that can be turned into a fiction story or an essay later on. Or at times, it may all look like gibberish. That's perfectly alright. This exercise is meant to get your creative juices flowing. Like most things, sometimes it works and sometimes it doesn't.
That's not the important thing. It's enough that you've spent ten full minutes writing, and more often than not, that's what's needed to keep writing. You can move on into a project in the works or somethng brand new. But you've primed the pump with the freewrite.