Quit simply you can tell if the ICO is profitable if the pre-sales have sold out and there is significant VC raised. Therefore a lot of support and faith from people who are putting their hard earned money into it.  Look into who are their biggest backers and what success and experience they have, as their judgment is highly valuable if they are successful in business. Also obviously a project which is quite established in its product or service...already tried and tested and optimally already being used! 

We have a bounty listing page at icoSource.io with some quality upcoming ICO's and bounty programs: https://icosource.io/ico-bounties/

Happy Bounty Hunting!