A very good way is similar to gambling. You buy them, and then sell them when the price has gone up. I managed to make 1.2BTC that way. However, be careful when you buy/sell as it will depend in the price. Always choose the right time to do so.
Them what?
Altcoins?
Yes, trade Bitcoins and other cryptos is a good way to earn, if you know what you are doing and if you are luck and the exchange you trade don't go Gox