Shapewear
Good-quality clothing. Go to Nordstrom and get a stylist to help. When you find something that works—whether it is a wrap dress or a certain pair of trousers or a flattering sweater—buy multiples/buy as many flattering colors as possible.
IMPECCABLE hair, makeup, nails. This doesn’t mean “overdone,” the makeup can be understated. But basically you can’t get away with a lazy ponytail and no makeup.