There are quit a number of ways people get bitcoins, the most notable one being mining. Its probably one of the best ways there is but comes with its challanges. it needs lots of technical know how on how to handle the computer generated tasks needed to complete a block, the equipment used aren't as cheap either, but the rewards are good. Trading too is a good way of earning, You can exchange other alt for Bitcoins. Bounty campaigns is also a god way of earning Bitcoins, you can change the bounty rewards into BTC
I doubt about mining part actually. Most of my btc miners friend stopped doing it. Rather than mining, there are many ways to earn it. Mainly day trading and also bounties like signature, social media, article campaigns.