It is a rare ability to persuade others to do what you want them to do when interacting with others. One or two days is not enough to learn some "yancha". More importantly, it is necessary to cultivate the ability to improvise, which requires long-term training. Your boyfriend should be a science student! What we science students lack most is perceptual thinking and sensitivity and cognition of new things, which is often very important in social communication.

So I suggest you find ways to make him pay more attention to the industry and think about the answers to difficult questions, so that customers can feel that you are very capable and, more importantly, very credible. After all, honesty is also very important in interpersonal communication now.

I hope my answer can help you!