Like a business or a company, you start from nothing when you meet a new group of people. Slowly but surely (maybe) you start to earn rep with that group. Rep is the currency of social status. If you meet the new group of people with a friend or two already, you have an advantage. Compare it to trying to set up a company: It's definitely much easier setting up the business with some capital rather than none - Your friends already know what you're like (with them) and help you build your rep, while you help them build theirs.

Stragglers who do not yet know any one benefit when they join the group. The more people you interact with, the faster your rep goes up, and the more people will know about you in time ("friends"!).

Nicknames and inside jokes do particularly well in boosting rep, if they're taken well, or if you live by your nickname lol.

Generally, the longer time you spend with your current group of friends, the more chances you get to boost your rep. So that basically means: eat together and eat slow so you have more chances to talk, walk together and walk slow for the same reason.

Extra credit for cracking jokes, despite the fact that very often, these jokes aren't particularly funny. BUT you get extra points for laughing at jokes to, so bad joke audiences don't mind the bad joke, and laugh anyway to get extra points.

Exaggerate physical ailments to gain pity points, or simply for that extra social point when your buddy asks you, "Are you okay?"

Mock other people and laugh about it with your friends. 2X points when the guy you're mocking is watching.

Yeahhhh that's about it. Tell you when I have more.