First of all find the good ICO, which have good idea, good team, good markenting and etc. When you find this ICO, try to find bounty campaign of this project. Bounty conditions important as well, but ICO success is first priority.
Do not just "find," but also take time to read about the team's past accomplishments and/or failures that could check their credibility. Read the goals and objectives of the project, and know if those will be all trustworthy.