Its a good question. I have my own tips for success ICO, project should be simple for understanding, team and advisors must have KYC, milestones should be done at time, by the way bounty and airdrops means not so much for me.
And the most important thing is to have capital, without capital, the project can stop at any time, as we know that most projects rely solely on money from ICO, when it is finished and available in many markets that sell, if they have capital then dev. can control prices.