If you want to earn a decent money in cryptocurrency, you must invest in Bitcoin which is dominating in digital currency market today. It has the most sustainability and profitability in the market right know, you can do both trading and long-term investment in bitcoin. I suggest don't focus on one coin instead distribute your investment in other coins like ETH or LTC etc... so you can avoid big loss in the long run. Its all about perfect timing of selling and buying your coins, you just have to be more patience in order for you to succeed.