Ask HN: You have a start-up idea. Now what?

Just curious what everyone's process for turning an idea that you just thought of into a real opportunity. Essentially the period between idea generation and actually executing on that idea (if there is a period of time).

My process is:

1. Lots of Google searching for potential keywords to see if anyone's posted about a need, or if there is a start-up there already.

1a. If there is a definite need, proceed to Step 2. If not, proceed to Step 1b. 1b. Look for start-ups already in this space. If there are, proceed to step 1c. If not, step 2. 1c. Is there a way to do it better? If yes, step 2. If no, kill idea.

2. Research and answer the following questions:

What is your idea? Why would someone want to use your idea? Who are your competitors? What if a big player enters your business? How will you differentiate yourself from them? How will you make money? How will you reach your customers? What is the time it will take you to launch? How much money will it take to get a revenue-generating version of your product? How will you convince people with complimentary skill sets to help you?

3. If the answers are satisfactory, tell friends and colleagues about potential opportunity.

It's a bit more complicated than this, but I hope this gets the point across. Not surprisingly, most of my ideas have been shot down at steps 1 (especially 1c) and 2.

Would love to hear everyone's processes and feedback to hopefully improve my own. Thanks!