I admit the center of my income is by joining bounty which is "Selling your items in exchange for BTC i.e(receiving BTC as payment for work or items sold)" from the list. I tried trading but not daily trading is which not effective for me, I tried investing but it took me years to earn a big amount of money, I tried farming but it also does not work, I am not sure if I earn through airdrops but I participated in so many airdrops before, for mining and BTC surveys I did not try those yet.
Now, I am getting attracted again to trading, airdrops, and farming but I will still continue participating in bounties. I it is all risky but its OK.