Is there something you wish you had known before joining TMP?

Not really. Due to the friendly support from the student coordinator and other employees at the universities, the start was very smooth and comfortable and nothing to worry about.
It is the best to find accommodation between Garching and Universität if possible, to make the most use of TMP resources.
I wish I knew more about the organization of courses and exams, which is very different from my country. Many courses are organized in "lectures"+"tutorials", and many of them require submitting exercise sheets every week. Core modules are way harder than normal modules. Even if they are 9 ECTS worth, the respective workload is way higher than other courses because they have many prerequisites that you might need to catch along the way.
No, I think I was well informed. Maybe, that the housing situation is really tough in Munich?