Legal way I can think of is working on a day job and then buying bitcoins every pay check. In that way you will keep your money safe and also an investment too for yourself.
Illegal way is through phishing, hacking.. you get the point. Also, if you are a crackhead, then you could sell crack or other illegal drugs in the black market in exchange for bitcoins.
I would stay away from illegal ways to earn Bitcoin, i believe in Karma so I guesss Ill go with the legal ways of earning. I can establish a business accepting bitcoin as mode of payment. I can tap faucet, and forward my referral in different forums so those who are starting out can sign for my ref link and I can earn bitcoins. Do task and freelancing. Look for a job that pays in bitcoin.