Hey! Thanks for following along.
I test my games with a group who meets weekly, and by running the game at local conventions. When I test the games I pay attention to rules that confuse players, and rules or parts of the game’s text that don’t evoke the theme of the game, and then I try to fix that in the next version of the game. I also look for characters, places, or bits of lore that the players come up with that I like and incorporate that into the game, with their permission.
I wouldn’t worry too much about having a lot of players to test your game, just as long as you are playing it between versions and not just designing by yourself. Like John Harper says, play and iterate.