I'll always recommend _Positively Fifth Street_ by James McManus. He doesn't really lay out how to do it step by step, but takes you along for a ride as to what the world looks like from that perspective. kinda.
The casino will ban you if you count cards in blackjack.
The sportsbooks will limit your action or ban you if the figure out you have an edge (or just see that you're winning or betting in certain patterns).
Frustrating is definitely a great way to describe the game, and emotionally crushing. Like imagine one is playing a 5/10 no limit hold'em game - so people are generally buying in for about $1000, unless they're from Spain. An extremely good player might have a longterm winrate of around 3bb/100 there. In 100 hands, there's every chance you'll be involved multiple pots, easily for thousands of dollars. And your long-term expectation is about $30 out of all of that. So you'll go through short term swings where you're up tens of thousands of dollars in very short periods of time, swings where you're down tens of thousands of dollars - all to get your $30 per 100. And you never become completely numb to the money, even after playing millions of hands.
Or when an online casino is not careful enough about how you earn the bonuses they give you. Things of that nature. There are people also who can do it at things like horse, racing or sports betting, but I never knew enough about either of those or wanted to learn.
My Predictit wagering has mostly been on the theory that exactly what this article says is true: people are betting who they like and the polling aggregators are better. I really just look for arbitrage opportunities or discrepancies between the market and 538 that are large enough to overcome the fees.
The fees are high enough to make it not happen a ton, but it does happen.
https://www.journalofaccountancy.com/issues/2018/oct/pro-gam...
but some deductions maybe yeah