Short answer: matching underwear
It is not something I paid a lot of attention to in recent years because for one reason or another, I didn't really care, but soon after splitting up from my husband, I located the local Ann Summers representative and found they did some exquisite underwear sets, so now whenever the sales are on, a new set is bought.
I found that wearing matching underwear does actually make you feel better about yourself too. It gives you extra sass in your step that the world will be able to see, unlike your matching underwear as that's for you know and no-one else to see (when you are out and about on your daily business anyway).
It is something that doesn't take a lot of effort, except if you need to take a little time hunting for the matching pair, turning out all the drawers and making a mess. A little organization helps too.
I now think what would happen if I went outside and had some kind of accident and I had to go to the hospital, how embarrassing it would be to be wearing mishappen underwear older than your children (if they are over 4).
Wearing matching underwear is the essential start to feel like a million dollars.