According to recent recearch, 56% of 2017 ICOs fail. And you know what? That's OK. 90% of startups fail but the rest grow so high that they compensate venture investors 90% loss and provide very high profits.
So the basic rules with ICOs are very simple:
1. Do the research before you invest
2. Diversify, diversify, diversify
3. Ignore news and HODL
There are a lot of ICOs which turned out fail, because it can't reach the hardcap of the project, people (investors) don't want to invest in that ICO, maybe it's because the project itself doesn't look promising, as we can see from the idea of the project itself, the devs, and the whitepaper of the ICO