1. Analyze the roadmap: check personally what the team has actually already done, and how realistic the plans are for the future,
2. Check team members for the reality of their personalities, find their past work and achievements,
3. Analyze how viable and relevant the project idea is,
4. Read the technical documentation carefully.
To learn how to analyze projects well, you need to become a detective)
some projects always change their roadmap in the middle of their project development these days. using so many excuses to delay the project. so i think checking the roadmap isn't very effective to evading some scam project.