You need to be very creative and artistic:
As you will be designing clothes, one quality you just cannot do without is creativity and artistic sense. You need to turn raw materials into beautiful costumes and accessories. This requires a lot of detailing and creativity.
You need to have an eye for detail:
It is very important for a fashion designer to come out with some basic designs and then add detailing to them. Most of the times it is the detail which makes the clothes stand out. So to be a good fashion designer you will have to give a lot of importance to the detailing of the clothes that you design.
You need to have good understanding of color, texture and fabric quality:
Another important quality that you need to have is the understanding of the raw materials that you are working with. You need to analyze beforehand as to what design will look good with a certain fabric, how can you use it, which colors you can mix with it and so on. These small details will help you in making your designs and costumes look good.