Unfortunately, ideas are very illusive. You can have one easily. But if you don't catch it quickly the idea passes through you and is off in to the flow of consciousness.
As you probably already know, good ideas come and go.
So how do you retain or "catch" an idea?
Very easily. Just have a note card, journal or "idea" document on your computer and write ideas down as they come to you.
Then every week or even every month review your ideas.
See what makes sense.
Implement one idea.
Do that regularly and more ideas will flow to you.
When they do just repeat the drill of catch, review, implement.
Before long you'll be an idea master.
Special Note: The idea for this blog post came from an idea I caught and captured on a 3X5 card.