I would say that the best way to identify if an ICO is a scam or not is to read and research everything about them. First, read their whitepaper in its entirety. One thing that you will notice with almost all of the ICOs is that their whitepapers are littered with grammatical errors and appear as if it was put together like a scrapbook, some appear to have been written by a high-schooler. Look for fluffs and words such as the mention of the phrase "price appreciation", "guarantee", "put flag on the moon", "the first, the only" etc.. Whitepaper will tell you all kind of tell-tale of an ICO. It should be written for an average reader, not filled with marketing gimmick mumbo jumbos or words you do not understand as if they're trying to impress you.
Once you're finish reading the whitepaper the first time, read it again. Then move on to their team, see who they are and what they've done. Look at their Linked In. Then look at the website and everything else. If you've completely satisfied, then you should consider if the project is truly disruptive, revolutionary, or technologically advanced. Avoid ICOs that mention Amazon, UBer, Netflix etc.. If an ICO is a good ICO, there is no need to psychologically try to manipulate people, all they need is just to present an idea. That's my take.