How do people make money from P2P?

So, I'm curious to know, how exactly do individuals manage to generate income through peer-to-peer (P2P) transactions? I understand that P2P platforms allow for direct interactions between buyers and sellers, eliminating intermediaries, but how does this translate into profit-making opportunities? Are there specific strategies or techniques that people employ to successfully monetize their P2P activities? And how do they navigate the potential risks and challenges associated with this mode of exchange?