Yes we can not predict everything that happens in trading, especially with new altcoins. To minimize the risk we should only trade the potential altcoins such as ETH, BTC, XEM, XRP.
Surely trading is unpredictable. No one can actually predict what is going to happen. But yes there are some tools that show you the analysis of the prices for some special coins that what the pattern with which this coin is moving is.
Then comes your own analyzing skills and you will observe and study the ups and downs of prices relating them with some events and give a rough prediction.