Go to your “ideas to write about file” and pick a topic. The bigger and meatier the topic, the better. Write as if you are on a tight, frantic deadline and have to come up with no fewer than 500 words and no less than 505 words to get your idea across. Go.
Reflect on what the tight constraints allowed you to do. Did it help you simplify the idea? Did it make you select more powerful words?