We have ideas for new products or services that could become new businesses. Exploring these ideas is fun; charting out how this could potentially work is a cool process. That analysis is fine, but we need to get away from the desk and test the idea.
It doesn't have to be a huge deal: the first best next step could be as simple as a few conversations with potential customers or people in the sector. The test could be as complex as attempting to sell the idea to someone.