Yes, while most ICOs are scams, there are genuine ICOs too.
i think Whitepaper give an indication of the whole business. firstly, it has to be more than 20 pages long. It shows that the team is passionate about their business. Secondly, it has to have a good detailed images of the product flow. Thirdly, whether the products are doable or not.
from the WP and website interface alone, most can see whether an ICO has put in effort or not.