When in doubt, wear a tie.

I substitute panty hose for tie when I think to apply this adage to my life philosophy. I am a believer in panty hose, and wear them as a physical reminder of the level of decorum a situation may call for. I am serious, without imposing an expectation of formality to others. By wearing a tie, or hose as the case may be, you are dressing yourself up without dressing down others. It says only nice things about you.