Some airdrops are worth it but most of them are only for promotion.

I make good money with investing in altcoins. I try to find an altcoin I believe in and try to buy low. I'm more a hodler so I try not to trade too much. Look at some recommended altcoins and do your research on them.

ICO's are also a good way to make money but they are 'high risk, high reward' so you have to do your research before investing in one.