Once you have a clear understanding of your target audience and your business goals, you can start choosing game mechanics that match them. There are many types of game mechanics, such as challenges, rewards, feedback, progression, competition, cooperation, customization, exploration, discovery, narrative, or social interaction, and each one can have different effects on player behavior and emotion. You need to select game mechanics that are relevant, meaningful, and fun for your players, and that also support your business goals. For example, if you want to increase engagement, you can use game mechanics that create a sense of challenge, mastery, or curiosity. If you want to increase retention, you can use game mechanics that create a sense of achievement, progression, or loyalty. If you want to increase monetization, you can use game mechanics that create a sense of value, scarcity, or urgency. If you want to increase virality, you can use game mechanics that create a sense of sociality, reciprocity, or advocacy.