Here is a list of useful adjectives for talking about clothes:
Small – 작은[ja-geun]
Big – 큰 [keun]
Tight – 꽉 끼는 [ggwak ggi-neun]
Loose – 헐렁한 [heolreonghan]
Thick – 두꺼운 [dukkeoun]
Thin – 얇은 [yal-beun]
Short – 짧은 [jjal-beun]
Long – 긴 [gin]
Fit – 딱 맞는 [ddak man-neun]
And this is how you can use them in a sentence:
This blouse is too small. 이 블라우스는 너무 작아요. [i beullauseuneun neomu jagayo]
This blouse is too big. 이 블라우스는 너무 커요. [i beullauseuneun neomu keoyo]
This skirt is too short. 이 치마는 너무 짧아요. [i chimaneun neomu jjalbayo]
This skirt is too long. 이 스커트는 너무 길어요. [i chimaneun neomu gireoyo]
This pair of trousers is too tight. 이 바지는 너무 꽉 껴요.[i bajeeneun neomu ggwak ggyeoyo]
This pair of trousers is too loose. 이 바지는 너무 헐렁해요. [i bajeeneun neomu heolreonghaeyo]
This sweater is too thin. 이 스웨터는 너무 얇아요. [i sweteoneun neomu yalbayo]
This sweater is too thick. 이 스웨터는 너무 두꺼워요. [i sweteoneun neomu dooggeowoyo]
This T-shirt fits me. 이 티셔츠는 딱 맞아요. [i teesheocheuneun ddak majayo]