The secret is to start 15+ years ago.
One benefit every collector had if they started in 2009 is experiencing a rapid and sustained increase in what their Pokémon cards were worth. Things you bought for fun because it was a personal interest of yours became accidental investments with massive profit potential. Here is an example from my own life.
I began as a set collector. I wanted to collect Base, Jungle, Fossil, and Rocket in Unlimited condition as my earliest goal. If you wanted sets back then, you could buy complete mint sets easily. These sets were still assembled from people’s personal closet collections. Ungraded mint cards were still an abundant norm. The phrase “pack fresh” was everywhere because people still opened and built these sets for fun.
I bought these sets easily. I built a complete collection in one effortless transaction. I held them for a couple of years and then thought these cards were too easy. I wanted to sell these cards and buy 1st Editions instead just because they were a more “premium card” to base my collection around. I sold my three sets in 2011. I was pleased that I actually made more money than they originally cost me. Would you like to see what those sets sold for?

The stone cold truth is that Pokémon cards used to cost pennies per card. More than that, they were free. Pokémon cards were free. If you were 18 years old and asked another 18 year old if they still had their Pokémon cards, they gave them to you. When I got back into Pokémon my senior year of high school, kids tripped over themselves to give their old Pokémon cards to me. I had stacks of binders in my bedroom from other kids I went to school with just happy to give them away.
Those same unlimited WotC sets I bought and sold for $40 now change hands regularly for $250-$300 in significantly worse condition. If I had held on to them, that would be a 7.5x increase in value - not even accounting for the condition difference. And I had thousands of cards. Hundreds of duplicates.
But imagine a different route. Imagine if in 2010 I had compiled inventory of these cards. Imagine in 2016 I saw the writing on the wall and send all these raw mint cards I’d amassed at almost no cost to PSA and received back a significant inventory of PSA 9s and 10s. Imagine I started selling my Pokémon cards on eBay consistently and build up a routine for myself in an era where there’s far few people doing such a thing. Imagine that every time I sell a card, I am making 7.5x on my investment. Maybe I’m making 10x. Maybe 15x! You are suddenly flush with cash. You can buy every Pokémon card you ever dreamed of owning.
That 1st Edition Base Set Charizard is $700 in 2012, so you buy it. You never thought I’d spend $700 on a Pokémon card, but why not? The card is the crown jewel of your collection for another few years. In 2016, the card is worth $3,000. By 2020, the card is worth $14,000. You finally sell the card. Now you have $14,000 from Pokémon, money you wouldn’t have otherwise, money that blows your mind. What do you do with it? You put it back into the collection. You buy more Pokémon.
The most successful collectors who made their wealth on Pokémon definitely did everything right when the iron was hot. There is a gap between the collectors who got lucky and the collectors who made their livelihoods off of the hobby. People who continue to run businesses and have learned the industry of the hobby inside and out are experts in what it took and still takes to turn a hobby into a business.
But the fact is also that we all made money off of Pokémon. Everyone who collected back then saw their collections 3x, 7x, 10x, 20x over time and that money opened doors to more cards, rarer cards, or significant real life gains. People have sold single Pokémon cards to make downpayments on houses. People have sold Pokémon cards to pay off their student loans. If you were there, you got lucky too and Pokémon probably changed your life.
Maybe you didn’t make it into a business, maybe it was a one-and-done turn around where you cashed out on your investment. But there was no secret recipe to be successful with Pokémon if you were there back then. You just had to be there.
The conditions to become a rags to riches Pokémon collector who turns their hobby into a livelihood no longer exist. The conditions for these successful businessfolks to maintain their livelihoods is more challenging than ever. My best advice is to go back in time and start in 2010.