the easiest : Hold, trading and lending

for long term i suggest you hold the btc
this is the not the safe way to earn btc with gamble, and joined the ICO(this is profitalbe but now maybe Dev just wanna rich his own with his Shit coins.)
In a way, youre right. Why I said youre right is because this time around its hard to earn or get anything from bitcoin unless you invest money into it. I believe those that invest money will make more profit and benefit from the Volatility rate which keeps on going up everyday.
Those that work without Investing wont earn much like that, though I do believe that there are jobs on Bitcoin that can earn you a lot of money, but it wont be jobs like faucets.