I actually started by dressing up casually in my Utilikilts with boots, regular socks, regular shirts and regular jackets. As time went by, I have dressed up in a proper jacket, hose, sporran, kilt pin and dress shirt. However, I still don't see myself wearing flashes or Sgian Dubh.

I wear kilt hose when the weather is cold. If the weather is warm enough, I would not bother.

I assume that most people tuck their shirts in, but I only do it half the time.