I think mining is the best way for earning cryptocurrency do not forget you should have powerful device. Follow the campaign is another way where such powerful device not required.
Mining is only for those people who have enough capital to spend on mining rigs and I think it's hard to mine right now so my best pick for earning money here in crypto world is trading. Trading is simple if you have knowledge on it, you can also earn huge amount of money like the earning you get on mining if you learn how the coins move in the market. Having strategies also help you to get a better chance of earning on any coin you'd buy.
But if you have no capital to start on, the best way to earn is by joining signature campaigns but it takes time to qualify for it. Airdrops on the other hand can also give you income in the future if the coin successfully join the market.