1. Signature Campaign (in this forum only)
2. Cloud mining (many scams)
3. Mining (need to invest hardware to mine)
4. Become a freelancer, provide your service and get paid (on freelance.com, elance...)
5. Sell goods to get BTC
...
With your number 4, you can use directly xbtfreelancer to get paid with bitcoins directly. Because those freelancing sites you have mentioned will pay your through PayPal or dollars. And I will cross out with cloud mining because that is will just scam you in the end. Better to do the remaining choices to get 1-2 bitcoins monthly and with hardware mining OP doesn't want to invest.