Each time I see a drawing and especially a fashion illustration I think about the followings:
– the composition is well arranged in the page? Are the visual elements centered or the composition has a center of interest?
– lines: are they thin or thick? colored or just black and white?
– anatomy: are they any problems regarding the drawing of the human body? are the proportions and the measurements of the body – good?
– the color: is it ok? is there something that bothers my eyes? maybe the juxtaposition of complementary colors or are they too many patterns used in an outfit?
These, any many others – I have to check them first. In time, this will happen in a second and you will immediately recognize the errors : if something is missing or if it is too much.
When drawing a fashion sketch you should always think about the modulated line. It is the line that helps you “colorize” the drawing, even if this one is in black and white. You should use 4 to 8B pencils in order to have a scale of many grays in your drawing.
Use soft lines there where the light comes from and darker, stronger and bolder lines in the shadow – as in my drawings below. Use lines, dots and surfaces to create patterns and structures – to make the illustration nicer. Click on the images to see them bigger.