Tip #2: Raid the fridge
Take two minutes and throw some essentials in there, too: mini bitters, hot sauce, simple syrup -- a 2oz medicine bottle/ dropper works well if you only have normal-sized bottles at home -- and a bag of lemon/ lime slices, olives, pearl onions, orange rind, celery sticks -- whatever your favorite drink calls for. Seriously, it takes five seconds to slice a lime and throw it in your carry-on; it'll make all the difference.
Tip #3: Final grab from the food court
Channel your inner-McGuyver (who will later meet your inner-James Bond) and filch packets of sugar and pepper, then buy a can of Red Bull, a pint of chocolate milk, etc. Don't forget to snag a large cup, lid, and straw from the closest fast food joint if you're mixing something traditionally served in a highball.