For something like this, I would suggest leaving your work alone for a while. And then one day read it again. Since you don't have much memory of it, you can better judge your work. It'll be more of a surprise if you had in any plot twists or something.
Yes! Absolutely! It matters what your character wears because clothing is a way to show off who someone is without words. (Though I seriously don't recommend making a 4 paragraph description about what they look like :/ )