I've found that ICO's are almost identical to OTC pump and dumps - they're much less sophisticated versions of the same thing
Opportunities that are marketed as investments first, products second. Website homepages that resemble the "investors" section of ordinary website with no actual "product" presence. Vague products in markets that are easy to obfuscate or fake. Affiliations that can be purchased. High profile board members or investors who can be purchased. Social media footprint where people talking about the stock outnumber customers, etc.
If you've spent any time in Yahoo! message boards or Seeking Alpha looking at the hundreds of reverse-IPO's and pink sheet startups you'll recognize all of the same scams (and some of the same names! cough McAfee cough-cough)