Sometimes the ideas I get for stories are fleeting.
Sometimes they stick around.
The ones that stick, that I just cannot get out of my head, are the stories I begin to write down.
Right now, I am working on three ideas. One is the Sequel to Clifford's War. The other two....Well, Let's say, that I am not ready to talk about them yet, But I am really excited about them.
I have other stories in my head that are lingering, but I am not ready to start putting my thoughts out there yet. They have to mature first.
How do I know they are ready? I just can't stop thinking about a scene and a plotline. I begin to create characters and backstories, and the story continues to grow in my mind. It grows so big, that if I don't start writing it down, I will start to lose it. That's how I know.
To me, there is no such thing as writing too many stories. If your ideas are bursting to get out, let them out and write them down.
You may just get excited to see how it develops.