Rule #1: FOMO is dumb. We all live different lives in different places with different stresses. We all have different families, friends, finances, goals, hair styles, belly button lint, whatever. We all have loads of fun/laughter/adventure sometimes, and other times we have to hunker down at work and barely come up for air. Feeling bad about missing out is downright silly, because we can't do it all ALL of the time.
Rule #2: (related to Rule #1) Social media should be a source of inspiration: Feeling jealous of amazing instagrammed food? Let that be an inspiration for your next girls night out, or perhaps your own at-home cooking adventure. Is someone on twitter literally on top of a mountain looking all bad-ass? Awesome! Think about your own (figurative) mountain you are conquering today. It may only be a mountain of laundry, and that's okay. Need some words of wisdom? Follow folks that post cool articles/good quotes/interesting observations. I find that Mario Fraioli is always posting stuff that fits the bill.
Rule #3: 90% positive/neutral, 10% negative. A vent tweet here or there is totally encouraged, but keep in mind that the negative energy you put out into the world is bound to influence others. 'nuff said.