Add an actual design, not just random apparel. Consider who they are, their personality, all that jazz and design the character based on those.
Going for an edgy assassin, try black laced leather with a dart belt, knife, hood, tall boots, gloves, loads of belts in places they probably aren’t even necessary in, capture the character in their appearance.

Want a pure and good hero, maybe steel plate armour with a pendant of his dignified fictional religion, a glistening sword in hand and a white and blue colour scheme to promote the good guy look.

Just try to fit in as much detail and coolness in as possible, avoiding that stickman look at all costs.