I've seen You're Beautiful, Boys Before Flowers and Sungkyunkwan Scandal and I disagree. I didn't really like the female characters from these K-dramas.
I would say No Eun Seol from Protect The Boss, Sung Shi Won from Reply 1997 and Kim Sam Soon from My Name Is Kim Sam Soon.
My first Asian drama was Sorry I Love You. I started watching Asian dramas 3 years and 7 months ago. I've watched 102 (wish I had time to watch more!) and I watch Korean, Taiwanese, Japanese and recently I've started watching Chinese dramas.
Akira Kusano (Nobuta wo Produce)
Wataru Kurenai (Kamen Rider Kiva)
Tsukimori Ryouske (Tumbling)
Shinjo Kei (Rookies)
Yufune Tetsuro (Rookies)
I would say No Eun Seol from Protect The Boss, Sung Shi Won from Reply 1997 and Kim Sam Soon from My Name Is Kim Sam Soon.