Well a good way that I know is to read a lot about past ICOs that were successful and have coins or token that are still with us today going strong and improving. Then, read about ICOs or coins that have failed and are of to no value today. Doing this you will learn the similar traits or parts that made some ICOs become successful until today and the things that made the failed ICOs come short or become completely worthless today. After that, go and look for ICOs that has some of the qualities that the past successful ICOs had. Easier said than done but can make you earn millions if not thousands if you manage to do it right.