if you want to trade with low risk, trade a coin with high marketcap like ETH,XRP,DASH. those are quite stable.
or if you want to trade with high risk, choose any low marketcap coin, higher the risk higher the profit
Taking a calculative risk is very important because if you invest in any coin than chances are that instead of going up generally such coins are dumped badly and it may not rise and you will lose your money. Its better you invest in some known coins where chances of making profit is higher which is more secured and almost guaranteed.