Creases essentially, clothing is dependent on the types of fabric etc.

So if you have velvet it’s softer and sort of less likely to crease and wrinkle whereas something like linen will.

It purely depends on fabric and such so just think, for what piece of fabric said character is wearing, how much the fabric be?

Example:
The red vest is likely made out of thin layers of polyester or cotton. If you have jeans they’d be thicker and crease more.

For the above try and add some creases for the red vest, reduce the width that the top of the trousers has as it is hardly sitting on the bottom of the waist as it should so it looks weird, too big almost.

Layer the shoes beneath the trousers if they are regular shoes, if boots like the above and you want boots than above or below is your choice.

Structurally the Stickfigure is sound so it is just detailing and maybe design alterations.