Never make the mistake of not packing flats. Whenever you have to spend an entire day in (semi-comfy) heels, you should always do your feet a solid and bring a pair of flats you can change into at the end of the day. Or even a pair of comfy Crossfit shoes or sneakers--whatever floats your boat--if it means your feet won't hate you in the morning.
No matter how "comfortable" you say your dreadfully fabulous heels are, they will never be as comfortable as flats. Never! And I don't ever want to be that idiot (again) walking around barefoot on the dirty city streets like a complete train wreck. So gross.
Lipstick is no better. I've always been into lip glosses and that won't ever change because lipsticks tend to make me look like I'm wearing fake lips. Bold colors over plump, and trust me, I don't really need any help in the lip plumping area.
I have a bad habit of wearing a handful of the sames clothes in my closet over and over again. Therefore, a have a ton of pieces that only see the light of day on special occasions, when they're in season, or when I feel bad and want to give them a spin. Because of this, I will some times take something from the back of the closet and put it on only to notice that it now has closet smell.
This is clearly caused by having a closet that's stuffed to the brim. So the moral of this story is to air out the clothes that you don't wear often in advance of wearing them, or keep some potpourri in your closet for the rare occurrence when you decide to break out the crop top in December. Or simply get rid of some of your shit.
If you don't know how to pronounce something, or you think you're pronouncing it correctly, but aren't quite sure, just Google 'how to pronounce..." and a YouTube link will say the name for you. Or you might even be able to hear it said in a Vine video.
I used to say all sorts of brand names incorrectly, i.e., Hermes and Miu Miu, but now I've figured it out thanks to Google. The same can be done for social media brands. Don't say the brand name incorrectly when you're talking to someone who works for the brand--that's just foolish. Let Google be your homeboy.