Here on Bitcointalk. There are tons of projects, that are posting their ANN every day. It usually costs a lot of time, to find the good one. You can also check the influencers of the crypto would, what do they recommend.
First, you can check the evaluation of ico on rating sites such as, foxico, icomarks, trackico and so on. The best ranking site in my opinion is icodrops. then do your own research: look through the white paper, how much people in the community, make an assessment of the community, team, partnerships.. if the project has a bounty, a good one can still be determined by the number of high ranked members of the forum in the signature campaign.