Trading is a good way. Setup an account on an exchange and buy a little of a cryptocurrency you are interested in. Study the charts and try to buy in a dip of a popular coin. Once you bought a coin, set a sell price a bit higher enough to offset your trading fees and to make a small profit. Rinse and repeat until you grow your stack. Just remember to buy low and sell high. 
I agree. Since we're in the trading thread, I would focus on it. Trading is a good venture for those people who have a good feel for the market, since the cryptocurrency market may go up and down in a very quick pace. It's more of a short term venture because trades may be down from as low as minutes or hours up to days at one time, that's how active the market is. Also, it fits those that have a diverse porfolio of coins because they can do more trades than just focusing on one coin at a time.