Guess this is pretty obvi right. Everyone underestimates how simply playing to another person's needs is so key. People like doing things that make them feel good. Humans are innately selfish and like things that benefit them. Even when we do things for the benefit of others, it also benefits our own emotional needs. This is a human trait that we all need to keep in mind and use for the benefit of that individual and your self. Mutual wins are always key. If you know that a potential acquaintance loves charity work and you really want to connect with them, then volunteer at the event or help them get a celebrity guest. These goodwill points always make a colleague feel good and makes them want to also help you.
Engendering a good emotional feeling in someone can help you garner that first sale or help you get an introduction to a new mentor. With gatekeepers (secretaries, executive assistants, associates) for example, recognizing the importance of their job and position and engendering feelings of importance in these individuals can help you get a meeting or talk with a key customer or influencer. Authentically providing a benefit to a peer can go a long.
In the end, everyone has something that motivates them, has something that makes them feel good, and has something that would benefit their life. Keep in mind that people remember what you did for them and how you made them feel. This can come in the form of nice compliments or nice gestures, but either way people love it. Life is a people game.
Disclaimer: Don't confuse the external/internal benefit that you provide people with manipulation. You aren't lying or deceiving someone for the benefit of yourself. You are providing a win/win for everyone.