it's depend economic system:
more people buy, the price will up
also if more people sell, the price will down!
you can use Technical Analysis to predict the price
also you can search news about your coin that you invest in
hope you helped
The price of Bitcoin, Ethereum and other virtual currencies are determined by their demand and supply. Ethereum, for instance, in 2017 controlled about 30 percent of the total market cap due to its high demand by investors of ICOs at that time. Asides from high demand influencing cryptocurrencies’ price, these are assets that have a limited supply which is aimed at improving their value.