A detailed analysis of ICOs is very difficult and the overall bearish market is another factor for the success of an ICO. I don't know if it's the best time to invest in an ICO.

But to your question: Personally, I think, the most important thing is a research about the team, it's characters, amount of people for this project, qualifications, experieces and previous actions. This is very important and for doing this you can use google or social websites to get more informations about this team.
Another one ist the project. Read website and whitepaper and ask yourself if the solution offered by this ICO would be neccesary or is it another copy of existing projects. The market for ICOs is very hard now and you need a good idea to exist.
After all ask questions in the telegram or via mail if you have concerns. A honest team will answer them.
You can also have a look to the price of the tokens and the maximal supply. Some ICOs are very over valued and will dump instantly after listing on exchanges.

Please be careful by looking at ICO-rating-platforms. It's no secret some are involved in shady businesses getting better places for projects if they pay...