What should I say and do to make people like me when I go to my mother-in-law's house for the Mid-Autumn Festival for the first time?

Be diligent, no matter what your mother-in-law does, run over and say "I'll help you" (you can ask whether you can do it or not). For example, cooking is to help wash vegetables (if you can do it, you miss your hands). These are secondary things, mainly to find opportunities to chat with my mother-in-law, gossip and toast while eating, so that I won't be ignorant of what to say.