There are some ways to know good coins to buy during ICO and after ICO. You have to confirm that the project has a product attached to it. The product must be a valuable one that tends to solve mankind problems. Some of the product will be aPP, some may be medical solution, telecom roaming solutions and trading platform.
There are many factors on how to determine the characteristics of a coin whether it is good or bad. Base on my experienced inorder to determine the good characteristic of a coin you must look for its graph on how does it rose up basing on its history until its present graph. There are many algorithim to solve the behavior of its graph and if you do have any knowledge in solving algorithims then you can truly determine how good it is