Well - I'm not anything of an expert, but the advice I'd give is as follows;

Don't cut off any of the fabric.

If you can, turn up the spare fabric along a line of the pattern, fold it just once and then press it along the new lower edge - carefully, on the inside and use a pressing cloth. That will make it much easier to sew.

You will probably be keeping the kilt far cleaner than 'older kilts' and although eventually it would probably stop unravelling it might be with quite a long fringe and even some sliding and distortion of the threads within the fabric - far better to keep the selvage.

Secure the end of the thread to the back of the hem by making two small stitches and slide the needle eye first under them both to make a half hitch.

Work from the inside of the kilt. You might find it easier to fold the hem so you have the edge of the fabric and the line where it will be sewn clear of the rest of the fabric.

Make a small stitch vertically in the outer part, insert the needle just above the level of the selvage, catch perhaps two threads and bring the tip of the needle out and through the edge of the selvage. Do the same thing a little further along the edge. The distance between stitches depends on the thickness of the cloth. You are making a sort of spiral of thread through the edge of the selvage and just catching the fabric at the same level where it needs to be held. Don't pull it too tight, the pressing will actually make the fold, it just needs to be held to stop it getting turned down again.

When you have sewn the hem you can press the pleats in. A small piece of thin card pushed into the fold might help to get a sharp edge. The inside of the pleat will want to fold the wrong way. Remember to use a pressing cloth.

From the inside you see diagonal lines of sewing thread, the end of one stitch is vertically above the start of the next. That makes a very small vertical line of thread on the outside. You should match the colour of the sewing thread to the line of the pattern on the outside. If you can't get an exact match, then go for something slightly darker as that is less visible than thread which is slightly lighter.

Hope that helps.

Anne the Pleater