You do not know and there is not really a way to know beforehand how a project will do in the future, even if you do your due diligence and you find out that the developers are who they say they are, they are talented, big businesses are behind the project and the market conditions were ideal this will still no guarantee you will get positive results.

By doing all the above you can take a calculated risk, but you are still taking a risk and as such you cannot expect to predict perfectly what will happen with each one of those new coins in which you decide to invest, so you will have to accept whatever outcome you get out of your investments.