Play the game. When you notice something isn't fun, remove that thing. Repeat. That's playtesting. If you want to watch someone doing this, pull up some videos

Play the game. When you notice something isn't fun, remove that thing. Repeat. That's playtesting. If you want to watch someone doing this, pull up some videos of Notch making games. That's the process he follows constantly, from start to finish. He also has good taste, which is why his games turn out well. If you don't have a nose for what's fun and what isn't, you have to take feedback from your users. If it's a multiplayer game, you should take feedback from the most competitive users, ideally from the people who are trying to form pro tournaments around your game. Casual players don't care what you do to the game, because it doesn't affect them much. But competitive players are your lifeblood, even if you don't know it yet. A competitive scene is what carries a game after its shelf-life has expired.