What goes into a quality bow tie? It is surprisingly simple. Start with quality fabric of the correct weight. Fabric is important because it effects how the knot will dimple and bow folds on the ends. The lining can help with this but heavy lining makes a stiff tie and a fat unappealing knot. It can also make the tie difficult to tie.
Woven silk bow ties are probably the easiest to make and printed silk presents the most problems. Printed silk is usually light weight, needs a great lining fabric, and will tie a huge floppy bow with a tiny knot if it is tied wrong. The best tie makers address this problem by using heavier silk, as much as 36oz, that will hold the shape without being bulky. The only problem with 36oz fabric is that it is VERY expensive so you will not see it very often or at a price that will not make you scream. And the more colors printed on it the more expensive it is.
All ties are cut on the bias, at a 45 degree angle to the edge of the fabric, but I think this is even more important for bow ties. The little bit of stretch that comes from the bias cut is just enough to tighten the bow and have it stay without getting loose. All pieces, including the lining, should be cut on the bias.
Lining fabric is the easiest part. Just pick something that gives the right feel to the tie. I use cotton a lot but I have also used heavy silk. Then create a pattern that is symmetric and proportional.
The last thing worth mentioning is the pressing of the sewn tie pieces. I think pressing could be the most misunderstood part of construction. It is how fabric is shrunk, shaped, creased. There is no substitute for knowing how to press. After the pieces are sewn they look like tubes. If silk is pressed with too much heat it shines. Even worse, an indentation from the seam can be pressed into the fabric. In bow ties, if you see a raised border along the edge of the tie it was not pressed correctly. Either too much heat or too much pressure was used.
So that’s it. Not difficult, just takes patience and a commitment to use the best materials.