This below is one of doitinvest.com answers to the linkedin questions there. It might be interesting for you, though.
I tend to agree with what has been written below. If you have a project, you should do first an evaluation of it by yourself, then build a solid business plan. The business plan will help you to drive the start-up through the early phases of the development, who are the most critical. It also helps you to clarify what the start-up should be doing and how. Then, and only then, you should present this plan to potential investors.
Every “angel” has his/her own metrics of measurement, but obviously two are always on their sight: