...^This in particular strikes me as a very misguided way to think about character design. :T Like, if you couldn't decide on what clothes your character should wear; would you just have them go around naked?? The thought process doesn't make sense to me...
Baldness isn't just the absence of hair; it is in itself a design choice. People won't look at a bald character and wonder if you had trouble thinking of a hairstyle; they will wonder why the character is bald and why you decided they should be bald, and how the trait fits into their design and character concept.
People assume purpose when they look at character designs, and naturally you should make design decisions with purpose.
Anyway, when it comes to adding interest to character designs, I think most can be improved through at least one of these four avenues:
Color: For some reason, a lot of people behave as if clothes only come in white, black, beige, and (denim only) blue . In reality, there's a whole wheel full of colors to play with; use them!
Character: People tend to wear things that reflect their past experiences, present circumstances, likes and dislikes. An old college sweater, a band T-shirt, merchandise from their favorite anime, their most comfortable pair of pajama pants. Adding just a small personal touch that says something about the character can make a design more unique.
Patterns: If you must put your character in a bland T-shirt, at least make it a T-shirt with a stripe. If they have to wear jeans, throw some embroidery or ripped patches on there. Often just the bare minimum addition will immediately improve a generic article of clothing. TL;DR, when you decorate clothes, they tend to actually look interesting!
Accessories: Jewelry, hairclips, belts, hats, gloves, backpacks...the list goes on and on. If a design looks empty and unfinished, often a smartly placed accessory will do the trick. This is another thing that frustrates me when people forget it; very few people leave their homes wearing ONLY the clothes on their backs, and yet so many characters are designed as if bags and accessories don't exist.
Most importantly, I think the key to doing a good character design is knowing the character. Think about the way they act, the way they live, and the way you want the audience to see them, and base their clothing on those factors. And if you don't have ideas of your own, go out and find inspiration! For starters, look up characters who act like yours, and take note of how they dress and how people draw them. Look up each article of clothing they wear to get more reference if you have to. Of all the kinds of artistic research to do, this is arguably the easiest.