Assess/review the technical and economic feasibility of the idea.
Assess/review the sustainability of the startup you are going to create to exploit the idea.
Assess/review the "business plan".
Assess/review the opportunities.
Assess/review the risks.
Assess/review what the competitors are doing.

You can assess/review all such aspects yourself or, even better, you can ask a third party to assess/review them for you... it can certainly help catching the opportunities and handling the risks while following your business plan...