I used different technique when creating the clothes meshes. I found that the best way to make clothing and fit it to my character is to select a part of the body in the shape of a shirt or shorts for example and duplicate it. I created the knickers and the brassiere so. In the process of creating meshes I used modifiers such as Mirror, Solidify, Subdivision Surface. I was ready to unwrap them. But then the question about sequence of applying modifiers arose in my mind. Well, I decided to do some experiments. And here are the results with comments.
The first example is the dress. The modifiers are not applied at all. It seems that it was not good idea to use flower patterns. So, the first advice is: apply Mirror modifier before UV map unwrapping for patterns clothes.
I applied the Mirror modifier before UV mapping of the shawl. I wanted that the shawl fabric would be a little bit transparent and may be glossy.
As far the last couple of clothes, the Mirror modifier was applied before unwrapping. The Solidify modifier was applied only in the brassiere case. As a result, I had to texture also inside part of the brassiere. I used Transparent BSDF shader for making the edges of these clothes transparent. I am quite satisfied with the edge of the knickers but inside part of the brassiere edge must be fixed. So the second advice, don’t apply Solidify modifier before UV unwrapping if you don’t have some special reason for that.