A natural, genuine, carefree smile is the perfect way to let a girl know that you like being around her. It will also let her know that you’re a happy person, and since happiness can be contagious, she’ll associate positive emotions with you. If she returns your smile, you can bet she feels comfortable around you. This is a great way to gauge her interest level. As you talk, notice if she gives you any signs or hints that she likes you or if uses vaguely romantic language. She could also show her interest in you by nodding frequently or repeating some of your phrases.  To start a conversation, you can ask her an open-ended question about class, work, or pop culture. It could be something as simple as “what do you think about this band?” or “how’s your day going?” Don’t fret if the girl you like doesn’t initiate a conversation with you. If she likes you, she may be too shy or nervous to do so! Even if she seems like the most confident girl you know, she may have had a bad experience in the past or simply may not be ready to approach you yet but will be receptive if you start the conversation first. If you’re already friends, starting a conversation will be easy. In this case, the most effective way to tell if she likes you is to pick up on body language cues or to see if she treats you differently than she does her other friends. If you like the girl, put your best foot forward by remembering a few small details about the things she tells you. Listen carefully to the things she says so that you will have them for future reference.   For example, if she tells you the name of her favorite band, bring up one of the band’s songs during your next chat. She’ll be impressed that you took notice! If she wasn’t already interested in you romantically, she might start to reconsider once she sees how attentive you are. Talking also provides another opportunity to observe her body language, so watch for physical cues such as subtle touches. Only do this if you actually do like her and if you get the sense that she likes...

How would you rephrase that briefly using Vietnamese?
Mỉm cười với cô ấy. Bắt chuyện. Luôn chú tâm. Thổ lộ việc bạn thích cô ấy. Mời cô ấy đi chơi Nhìn nhận các tín hiệu của nàng. Tránh việc phân tích quá mức.