Ask your mom or dad.
Look in a book that has ideas about how to get ideas.
Sit down and think super hard about getting a good idea.
I had tried all of those things at other times and none of them had worked even one tiny bit ... especially number three. Sometimes it is better to try to just do normal things instead of thinking really hard about getting an idea. Then after a while, the start of a good idea might just pop into your head right at the moment you aren't even thinking about it. It is not good to be thinking, Is the good idea going to happen in the next two minutes? That doesn't work either.