There are many shoe styles: low heel, high heel, sporty, boot, etc
The important thing when designing and making sketches of shoes is to consider every possible variation.
It might happen that a leather low heel sporty looking shoe with a high heel design might not look very appealing but maybe if you take the same upper part of the show and via design sketch replace the high heel for a low heel it might look very nice.
It is expensive to develop the machinery, pattern cuts, etc to manufacture shoes so sketching them before hand with every possible combination of heels, colors, materials, badges, designs, etc is the correct way to design shoes. This apply to male or female shoe design but in general male shoe design is simpler due to the fact that in general male shoe don’t have high heels so the options are a lot simpler.