Here are some few ideas how.
Pretty bad ideas.
1. Betting - I tried betting some at freebitco.in at a football match, a 50-50 chance and a test of luck
Relying on betting for income especially if you don't have a clue what you're betting is a bad idea for someone not familiar with this.
2. Faucet
Waste of time for years.
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.
Cloud mining which is in 99% cases a scam is something different from actual mining with your gears, which is actually the only way from your 4 suggestions that can earn you a few dollars
if you have cheap electricity.
4. Writing for a cryptocurrency blogs - there are many websites that accept guest post and pay you for it like coincentral.com
With the influx of wannabe illiterate crypto bloggers this has become something as profitable as faucets.
Let's not forget that you don't need to do anything special to earn bitcoin. You can pretty much earn bitcoin the same way people earn other currencies: jobs, gigs, businesses, and such.
I don't know why some people try so much to earn directly
BTC wasting in some cases ten times more effort and time or not getting anything at all when they could simply earn fiat and exchange it to
BTC