1. Betting - I tried betting some at freebitco.in at a football match, a 50-50 chance and a test of luck
If you're a fan of gamble, then you might find betting a good sport for you.
2. Faucet - faucet is well known for some dudes who want to earn free bitcoin but it takes time to save even 0.5 bitcoins
Faucets is the number one bitcoin earner, with no capital just time and effort you will get some bits. But don't give some clueless people this hope that they will take time to save 0.5bitcoins coz that will probably take them 10years, maybe 5 if you find a good one.
3. Mining - very well known for investors but you need either a GPU (graphics processing unit) or an application-specific integrated circuit (ASIC) in order to set up a mining rig. There are also many scam and fake mining websites so be careful.
Mining is difficult to do now, there are less rewards due to halving and the competition is very high driven by the mining pools.
4. Writing for a cryptocurrency blogs - there are many websites that accept guest post and pay you for it like coincentral.com
Hmmm It is quite new to me.
You can write down what you do to earn some bitcoins, I will be interested.
Just like betting, we have trading this is the best way to earn cryptocurrencies but this is risky if you got no knowledge about what you are doing.
You better study for like a month before entering trading crypto.