#1: You don't want to use a hat to protect your hair from rain. It seems like a good idea until a gust of wind makes that hat fly off your head. Then you're running around in the rain, awkwardly bent over, while you chase a hat that's rolling down on the wet sidewalk. Not exactly the best way to preserve a blowout.
#2: You'll need to switch up your accessory game. Armfuls of bracelets and some layered necklaces? Sure. But chandelier or other statement earrings make for too much going on above the neck when you're wearing a hat too.
#3: You'll want to think about that hat like it's a pair of sunglasses, and choose one that suits your face and frame. If you've got a big jawline, for example, a cowboy hat can help balance it out with that wider brim. But if you're petite, a cowboy hat might overwhelm you. It's a little bit of trial and error, so make sure to try new styles on in front of a mirror before you commit to shopping for them online.
#4: You don't want to pack certain hats in a suitcase. Like straw ones. You might think it's resilient cause it's not, like, a silk dress or anything, but if you sorta smush it in your weekend bag you'll likely end up with a dent in it that's hard to get out. Be gentle and cautious with those hats, or they'll lose their original shape.
#5: Finding a hat that fits isn't like finding jeans that do, but still, you'll want to pay attention when shopping online. Most of the hats I've seen online measure 22 inches in circumfrence, but not all of them keep those standards. This one, for example, is only 21 inches, so if you've got a big noggin, it might not be for you.
#6: You'll want to choose fabrics that aren't too matchy-matchy with your outfit. That leather baseball cap is super-cool, but maybe don't pair it with your wax-coated jeans and leather top and go for a cotton baseball cap instead. Same goes for straw hats and straw beach bags: pick one or the other.