Unfortunately, you can't even do this today. This freaking crypto depression has destroyed everything. Even the coins that you do research and that look promising are losing the value and tanking without no obvious reason.
Look at Dash, Monero, NXT and the other promising coins. They have all dropped enormously in value the last 6+ months.
The more time that you invest to research about the coin that you are interested to invest the more you know and you are prepared to invest and you know if it worth or not. Because many things can happen, like developing anything new feature for the coin that probably will make the coin to be used more by people and the price normally will increase and you can profit.