Tai Chi is a martial art with no specific teaching material. What to impart to a student, and when to do so, depends very much on the student's aptitude and attitude. Indeed, to progress in Taiji, one must possess a positive and serious attitude toward learning, as teachers are often motivated to pass their knowledge on to students who are diligent, sincere, and respectful.
The progress of students is the ultimate form of affirmation and support to teachers. Students should try their best to not miss classes and practice regularly outside of class, instead of practicing only at class. At the same time, one should not be too hasty and try to master Taiji faster than others by consulting several teachers or sources at once. Confusion, after all, is counterproductive.
It should come as no surprise that students who are dishonest, complacent, arrogant, or even disrespectful to their teacher are unlikely to progress far. Those who treat their teachers as suppliers obligated to pass on everything in exchange for tuition fee miss the point that Taiji knowledge is broad and profound, and requires a lifetime, not a transaction, to acquire.
Ultimately, the only way to learn Tai Chi is modestly, with guidance from the teacher, thereby progressing gradually through patience and persistence.