I belong to the first situation. If you are a graduate student admitted to our university, it is very simple for you to contact the tutor, and the probability of making mistakes is particularly small. The most important thing is to know your own development needs, whether you plan to work or pursue further studies, whether you like moderation or strictness, the research direction you are interested in, and your familiarity with teachers. Because it is our school, I know more about the tutor and there are many channels to know. You can contact your tutor after confirmation. I was contacted by WeChat or by email. Actually, I don't have a contact template to refer to. "Sincerity" is always the most touching. Just be polite and express your truest thoughts.
The second situation is actually the situation of most candidates, and they know nothing about institutions and tutors. In this case, the first thing to do is to expand your own information sources and learn as much as possible about the tutors of the target major, their research defense lines, personal characteristics, academic output and other related situations. You can seek help through university fairs, social media, website search, HowNet article search, etc. The graduate website of the target university has all the research directions and contact information of the tutor, and you can send an email after confirmation.
Be careful when choosing a mentor. Ask yourself what you want and what style you like. If you contact the tutor, you can actually consult the teacher's usual academic arrangement, which aspect to focus on, and further determine your wishes. There are many experiences and tutorials online. I can refer to my ideas, but I don't need to listen to them all. What matters is my own judgment and sincerity.