I'm old per the calendar.

1) Dress for your body as it is NOW. Forget what you weighed 10 years ago. I guarantee that at 60 you will look at photos from 20 years ago and think "What was I thinking? I looked good!"

2) I'm not saying ignore current trends but if if you look spectacular in an item that is not currently fashionable (such as skinny jeans), just wear an interpretation of that or make the rest of your outfit very current.

3) Social appropriateness will make your life easier (crotch skimming skirts are best clubbing)

4) Don't be an asshole. I realized I was a judge-y jerk after an elevator trip with an immaculately pressed denim & rhinestone wearing woman with very carefully styled Farrah Fawcett hair (this was about 3 yrs ago - we were side-eying each other). I later realized that I possibly made her feel bad through a slightly elevated eyebrow. I do not do that any more. I was an asshole. I should have given her a friendly smile because she was very committed to the look and did a very good job of it.