You didn't do anything wrong but you are playing the game as it is, because I think roulette is a game of chance. Although I have seen some gamblers who is playing it a little different, like they bet on multiple numbers and sections ( you know, the color ones, the odd/even, etc... thing ). Sure they can win often this way, but most of the times, the profit that they can get is only tiny, or they are only break even. And maybe their purpose of it is only to wager more?
As some casinos gives you a bonus if you wager high enough. But as a beginner on roulette, you can stick to what you are currently doing. To enjoy, will depend on the people. As some can enjoy if there is no learning curve.
Yeah, playing on different pockets is quite a good strategy for winning in gambling. It depends on the amount of money the gambler wagers on each of those pockets and luckily the ball would stop at one. But the disadvantage is that the win may not be enough to cover other money spent on other pockets. Hence the roulette player needs to do it once in a while and try some other methods too, which is needed in maximizing the winning opportunities for the gambler. Op never made any wrong mistake, as some users above would think. Every gambling journey begins with a mistake and it's inevitable. Gambling professionals also make mistakes and may end up losing huge amounts of money. While his lack of knowledge could be a factor, it's not the main factor. A newbie can win in slot games. The strategies used by gambling professionals rely mainly on money management and rescuing them from losing lots of money.
However, the newbies may believe that casinos or some gamblers have a cheat code for winning huge money via gambling. But, they don't understand that everyone in the casino house is equal when it comes to prediction games like slots. The difference is now in the experiences one has about the slot machine. He may be sure of some results after spending a specific amount on the machine. Maybe on the tenth spin, he may be expecting a win. However, it's still risky, and the player needs to wager with a smaller amount of money, still. Or maybe take the risk of putting lots of money into the process. If he focuses on the demo mode, he'd be able to understand the other means of betting on roulette games, like staking on colors or number intervals. But, the wins he sees in the demo mode can be a nitro that can convince the player to try the real board. He'll learn better paying on the real board than the demo. His actions are still accepted, as a newbie in the roulette game.