If the angel investors like the founders & team, are excited with the idea/product and already see some initial traction what are some other due diligence steps they may take before writing the first check to the company.
The only due diligence a good angel will do are any of the following:
1) Ask anyone who they know that also knows you what they think of you;
2) Use your product to whatever extent possible.
3) Look at what others have invested in that may be competitive.
4) Talk with others who have failed with a similar idea.
5 ) Review legal docs related to the actual investment.
In rare cases, an angel may ask to take a deeper dive on analytics but this is in very specific circumstances.
Anything more than that is the sign of a likely bad angel investor who is likely wasting your time.