Clothing is a highly saturated category.
Ebay used to have "ebay pulse". I never used it but from what I've read, that was where you would go see what was the most popular selling items.
It would probably be better not to sell the most popular items because you'd have more competition.
Generally speaking, sellers do not reveal too many secrets especially if they are successful with a certain type of product. You will have to find what is best for you.
Non paying buyers deserve unpaid item strikes.