Find a job (part time or full time) that pays in Bitcoin
Start a business and have Bitcoin as the major payment system.
Do freelancing works that pays in Bitcoin
Offer whatever skills you have and accept Bitcoin as payment
You can mine for Bitcoin
Last but not the least,
You can also buy Bitcoin in exchange of fiat.
Consider Bitcoin as the fiat money you have. How do you Increase (earn) fiat?
It's the same for Bitcoin.
So meaning hardwork and strategy is the key to increase bitcoin, without hardwork we got nothing.
Simple to say earning profits in digital currency(bitcoin) need a extra effort and challenge to get our goals because bitcoin is now a new form of money use worlwide un the duture.
Trasing and gambling is the fastest way to increase bitcoin but learn it well before op do this way.