We don't know what is the real project and scam project, because as of now 90% of all ICO are scam. The one thing i really sure is before you trust on the project, you may know personally the team or meet up them to identify if the identity are real or not and they explain to you the real purpose of the project.
I don't know where you got this number from (90%) but the projects I participated in were not scams.
Not a single one!
The problem is that people are too lazy to thoroughly study the project they enter into (read WP, calculate profit, figure out the dates of distributing the reward, etc.).
Because of that Telegram chats are full of stupid questions that one might answer just by doing a simple 15-minute research.