How we look effects how we feel about ourselves, there's just no two ways about it. I have some significant advice for older women and I hope you listen.
First, NEVER wear yesterday's clothes. (unless, of course, you are on a two-day hike to the top of a mountain and just can't carry more clothes) After awhile, yesterday's clothes look and smell dirty, and they also make you bored and boring.
Second, rummage around and find something that reflects this season's colors. Most of us have clothes we've hung onto for twenty or thirty years or longer. Look and see. There might be a blouse or a scarf or a hat that is just right. If you have the means, buy just a few things to perk up your wardrobe every season.
Third, always wear underwear that fits. It's amazing how it will make your body look.
Fourth, never wear anything that is too tight or small for your body. Fold it nicely and put it away, or chuck it out. There is no way it will ever make you look smaller than you are.
Fifth, if you have decided to show a little cleavage, then don't show your knees too and vise versa.
You can look lovely your whole life. Every day. Enjoy that!