I've been with the game since the early days a bit after DEC was introduced, ever since I just played daily and tapped into all the different earning opportunities the game offers never really selling anything but instead compounding and using earnings to buy more cards. After I took some initial profit on the SPS at the start of the airdrop, I just staked everything I got from it afterward.

Basically, the key is to have a long-term mindset, some dedication and consistency and things will ad up. That being said, the biggest window of opportunity is likely a thing of the past even though I still see more growth. I wrote an article in the past on how to pull it off (See How to Get Rich With Crypto Play2Earn Gaming)

I can recommend Mobile MiniGames (used to be called Clash Of Streamers). If you are looking for something where you still get in early before it really takes off.