How should your face be in general when walking about (to the shops, uni, in clubs)?

I know smiling all the time is bad and will probably look like a typical nice guy beta type thing but my 'neutral' relaxed face just seems to naturally make me look moody. I always get people asking what's up or telling me to smile more.

Any suggestions?

Edit: of course relating to TRP. So how should an alpha's face be? Should a dark triad look moody?