I think it's absolutely key to join the Telegram and Discord channels after reading the whitepaper and ask questions and see what you get for answers.

Also, what is your reason for investing in an ICO?  This is important, because if it's to make money in the short term you may have a completely different strategy than if you are planning to hold in the long term.  I have seen a lot of coins that actually drop in value when they hit the exchange for the first time - naturally, if people who have the tokens from the ICO want to cash out, as it were.

If you wish to avoid scams, there are some decent groups out there that are actually devoted to ferreting out those scams - ConcourseQ is one of them.  That's a good Telegram channel. One technique I learned in one of the investigative groups was using IMGUR to look up "Team Member" photos.  Scammers usually use fake photos on their team shots and that's one way to reveal an outright scam. I found a scam on Craiglist trying to sell fake Bitminer s9's using IMGUR where their "CEO" was an image that was ripped off from an Instagram account of a surfer from Santa Cruz.  

Also, common sense.  The Plexcoin scam (the guy did jail time for it, so yeah, it's a scam) featured a whitepaper that flat-out refused to reveal the identities of the team members with some ridiculous excuse.  Not sure who would have invested the $12M that that project managed to collect before their assets were frozen, but don't be one of those investors!