The best way to check is to search everything about this ICO. The team, the community, the site, the founder, the idea. If any pf these or other things look suspicion, then you just pass it.
But it will not be that easy to pass ICO that will scam in the end because we will not know if the project is already running, and my experience of ICO scam is only seen at the end of ICO after they successfully deceive everyone to raise funds.