I believe when choosing an ICO to invest in you should answer several questions:
  1) What problem does the project solve? Is there a need for a cryptocurrency to solve this problem?
  2) Is the project's solution to the problem unique and if not - why is it better over other cryptocurrencies with the same value proposition?
  3) Is the team experienced? Can you find more information about the leaders in LinkedIn and the internet?
  4) Do the project have notable partners?
  5) What are the token economics? How many coins will be minted? Is there a total supply? What percentage will be for the team?
  6) Last but not least - do the project have a working prototype?

Of course you can go deeper finding more about the technology, the governance model, etc.
In the end of the day during time when the trading prices of projects from top 20 are 80%+ down from their all-time high, probably the smarter decision is to invest in them and not in ICOs. Just my 2 satoshi.