Part I: Parties and fairs
As these occasions are the right times to get a little tipsy and enjoy oneself, I'll stick to some hard-earned experience.
Acting dumb when needed, but the most important thing is to know when to act sober.
If you feel comfortable, show it and move around talking with several people. You never know where you'll find wisdom you can use on the words of others.
Ask things nicely, saying 'thank you' will take you further than not saying it. Basic manners.
If you see something you like in other people, tell them. It may make their day.
Be assertive, don't gossip. Avoid Schadenfreude, or at least learn first how to convincingly hide it.
And, more or less accurately, that's a little summary of my weekend (or how I'd have loved it to be).
Wonder if anyone reads this hoping to find a real guide for good manners... It's not.