There's no best strategy of earning crypto unless you are lucky to win a jackpot when playing on a crypto casino but the possibility of winning a jackpot or even just a significant amount is not guaranteed, but you take the advice from the first comment, look for a good paying job and then use part of your salary to invest on Bitcoin and other assets that you like, because that's the best way to get sustainable income, not by gambling or hunting casino bonuses.
Winning the jackpot? It's like 1:1000 --- not everyone can win the jackpot, and don't think of gambling as a quick way to make money because it can be misleading.
The best way to make money is to invest, work, do business, or do something that's low risk.
Gambling is high risk, so you won't be able to beat the bookies and win.