Like with anything, if it was easy to make money in this way then lots of people would jump at the chance to do it and the amount you could make would fall. Unless you're going to go the full stretch to become a streamer or video creator - which means a lot of hours playing games and building your fan base, then there are few magic tricks to making money in this. You might be able to pick up the odd skins or special promotions that are possible to resell in certain marketplaces, but again, it requires a lot of time in a game to realize these things. You're best off finding a game you like, play it for a while and think of original ways to monetize it. Nobody is going to hand you a silver platter of money, because it means that they would lose that revenue stream in future.