One idea if you want to earn bitcoin is whenever you have work done from a client, you can ask them if they can pay in bitcoin instead and tell them you wanted to have own a bitcoin, but of course you have to tell them how can they pay you in bitcoin. It is possible only if you have a skill that can attract clients to commission you, if you can't think of a skill then it will be hard to earn btc. Same thing with earning fiat actually. If you can't offer anything, you will have nothing. I can't suggest signature campaigns cause it's a lot of time to be in a campaign, airdrop will waste your time. There are so much videos about how can you get a few coins from various ways, but you have to know that you'll be disappointed by how much will you get from it. But if you really wanted to have a coin then you can try it.