Use your comment as an icebreaker to start the conversation. Look around and observe what is going on around you. Is there anything funny or interesting that you notice? For example, if it is lunch and the food truck hasn’t arrived yet, you can say “Are they going to get us water for this wait, or do they want us to die?” If you are going to remark on something simple, try to make it playful. Even if you don’t think of yourself as a funny person, you can still be playful. And playfulness is found to be very attractive to both guys and girls.  This playfulness will make the conversation fun and will help keep the mood light. Don’t worry, the first few comments you make to your crush are not going to make or break the conversation. Getting the conversation started is more important. So don’t worry too much about being smooth, and focus instead on continuing conversation. Once you have broken in with an opening line, move on into something you can talk about more. Asking for an update is a good question to ask if you do already know the person a little bit or you are taking a class together, for example. It is a good idea to acknowledge your familiarity with one another by talking about the thing you have in common. This will make the conversation less awkward, and you will also get a better understanding of what is going on with the other person in your shared thing. For example, if you are taking a class together you can say, “So how is your midterm paper coming together?” You don’t have to mention the fact that you are in a class together unless you aren’t sure that he or she knows. If you want to remind him or her, do it without making a big deal out of it. Say “So in English class, how is your midterm paper coming together?” It is not weird that you know that you share a class. If he or she doesn’t know, you mentioning the class first will tip him or her off and he or she will probably apologize for not recognizing you. Topics of conversation can go by pretty quickly, and so it can be good to have a couple...

TL;DR in Vietnamese:
Đưa ra lời bình hài hước, nửa đùa nửa thật về nơi cả hai đang ở hay việc mà các bạn đang làm. Hỏi thông tin mới nhất về điều mà anh ấy hay cô ấy đang thực hiện, đặc biệt là nếu hai bạn có điểm chung. Hỏi ý kiến của anh ấy hay cô ấy về chủ đề nào đó dễ bàn luận. Hỏi người ấy về vấn đề nào đó bất ngờ nhưng dễ trả lời. Mở đầu bằng bất kỳ câu gì nảy ra trong đầu bạn.