Hmmm, for a trad. kilt:

Above:

T-shirts are good, as are sweaters, long sleeve mock turtlenecks, etc... Even a fleece sweatshirt's good, as long as it's short enough not to cover too much of the kilt.

A leather jacket is a nice addition. Or, if it's too cold, a down parka or vest works...

Either a black or brown day sporran works well. Can go w/o if you have a jacket or sweatshirt with pockets. Don't usually do that, since I sometimes wind up removing my sweatshirt or jacket, then don't have any pockets.

Underneath:

Kilt hose. That's what looks best, IMO. With flashes. Darker colors with darker colored shoes. Sandals, however, no kilt hose. IOW, go barefooted inside the sandals. Soccer socks w/o the stripes also work, as do lighter weight cableknit kneesocks that are long enough to have a turnover for flashes...

With respect to shoes, pretty much anything goes. I've worn Timberland casual shoes that look sorta like a wingtip, but with a rubber sole and are dark brown. Works nicely, as do the black 8-eyelet Docs, a pair of hiking boots, or even running shoes.

Also, if you've a full head of hair, grow it out. Definitely helps, IMHO.

Otherwise, do anything you want.
-J