I'll bite- Wear your kilt in public, and start doing it as soon as possible. If you think you'll "fit in" in Scotland because you're wearing a kilt, I have news for you. Kilt wearing is nearly as rare in Scotland as it is in the U.S.

So if you want to get comfortable wearing the kilt, forget about treating it like a costume. Ditch the puffy shirt and pick up a sensible, modern button up the front shirt, golf shirt, etc, and wear your kilt to dinner. Or to the grocery store. Or for a walk in the park. The only way to grow accustomed to wearing a kilt in stead of pants is to wear it. In public.