There seems to be a big lack of information how to do sculpt clothing wether it’«s stylized or realistic, and I’m just shooting in the dark for the most part.
My stuff seems to look quite lumpy and it’s difficult to find information on the subject.
You can start with a simple low-poly version, using vertex groups and the Solidify modifier. This is the workflow I always use for stylized characters. To add more detail, You can apply the modifiers, add a Multires modifier, and continue with some sculpting.