To find a good coins to buy is you have to take a good look in some coins that there is a posibility that can help you earn a good profit in the future. Some coins that there is a unique products that may looks more attractive in the future.
I also agree that if you have a good view and use knowledge to infer that you will definitely find a good money for yourself to invest, is it really good or not? Nobody can confirm that is just a judgment on the market assessment.