I want to check out clothes at ease. So before sales, I go to stores and mark the clothes that I like and when sale starts I buy them online.
I want to check out clothes at ease, so... : ゆっくり服を見たいから...
before sales, I go to stores and mark the clothes that I like : セール前にお店いって好きな服に目星を付けて.
and when sale starts I buy them online：セールが始まったらネットで買う.
I want to be able to relax when I shop for clothes. So before there's a sale, I go to the store to check out what's there and make a note of what I like.
I want to be able to take my time in the store, so if a sale is coming up, I'll check out the clothes before the sale starts and choose my favorites.
この文脈では「ゆっくり（なにかをする）」は「take my time (doing something)」とか「relax when I (do something」と言います。
「目星を付ける」は「choose」「mark down」と言います。「mark」だけ言ったら、服に跡をつける意味になってしまいます。（それは罪でしょう？！）
「セールが始まったらネットで買う」は「When the sale starts, I buy them online.」「After the sale starts, I buy them on the Web.」です。
モロッコ 
アメリカ合衆国 
