There are many things and criteria which can be used to be a deciding factor to buy an altcoin. It all starts with the Project value and interest among the people so that they like the project and invest over there in that project and it is something which is what we called the Project quality and apart from the project quality i also go with the technical analysis so that i can filter out the best altcoins among the number of coins. Then I would like to time the entry and then it will be easy for us to track the profits and trade. This is my daily routine for deciding the best buy option for altcoin.