1. Management Team
2. Business Opportunity
3. Product/Technology/ Intellectual Property
4. Strong backers/ supporters/ potential customers

There are many factors - but instead of trying to cover all the factors, you should focus on the above 4.

The reason is very simple, any quality/ strengths of the above 4 can be described in monetary terms easily and impact 80% of the business value.

"To capture a promising market with attractive product/ technology from a strong IP will lead to a profitable business in the future. With strong backers/ supporters/ potential customers, the chance of success will be much higher"