I started out by 'googling' making a kilt and looked through the first few pages of what that trawled up.

A kilt is basically a length of fabric pleated onto a waistband, but there are various ways to form the pleats, and the more tailored versions have the upper part of the pleats sewn down and shaped and sometimes the material is cut out from the inside of the pleats to reduce the bulk, and then a couple of layers of material are sewn in to reinforce and line the area, called the fell. Below the fell the pleats are straight, not flared.

Normally the selvage is used as the lower edge of the kilt, so the fabric is cut at right angles to the 'normal' line, but for fabrics with patterns which are wrong when cut that way - such as pinstripes, corduroy or some DPMs (camouflaged materials) the fabric is cut across and joined.

However - be warned - the kilt is just the beginning. There are jackets, hose, flashes, sporrans and belts to be considered too, and then you get into coordinating the colour of shirt and tie, thinking of the purchase of an Inverness coat, various headgear, then researching your family tree to see what tartans you can wear.