One key aspect you want to do know is speaking to some of the workers in the casino can let you know which machine is hot. Poker's payout isn't big, but it can be a steady game to win tokens as a starting point. There are three types of games you can play to win tokens.
Exchange gold for some tokens, a good starting amount would be 500 tokens - these are the currency you bet with and later exchange for prizes. The first thing you want to do upon encountering any casino is to save your game first, and if anything goes wrong you can always reload your game and try again. The first thing you want to do inside a casino is to have a good starting threshold of tokens. There are two different casinos found throughout the lands of Dragon Quest 11, each casino with its own unique prizes. Sometimes you'll be unlocking powerful new gear, while other times you'll be unlocking things like the bunny suit costume for Jade. Like real life, winning at the casino requires a bit of luck, but since this is a video game there are some tips and tricks that can be used to get the odds in your favor. You'll want to spend time in the casino, then.