I focus on products that are within specific niches or are trending. I do not have very great tips for that niche as it's so broud although I think really visual marketing might be best. It seems clothing sites do well on instagram once you build a following.
Also you could target other pages that have similar style clothing to yours. Try and find really cheap keywords to target. Compare your CPC or cost per like until you have actual conversion numbers and then once you get your cost per conversion, you can narrow down on specific demographics. Maybe females from X country age 18-23 are your highest buyers. Then you only spend money on that.
Adespresso is a great product for split testing. Check it out and read their blog posts.