It all comes down to one thing, and that's the willingness to learn.
No matter if you go to a course or go through an apprenticeship, if you're not willing to learn and take the trade seriously, you're never going to become a good tiler, period.
A certain capacity for critical thinking is VERY important. One who just imitates others will never become better than the "others". To always examine what oneself does, and what others do, and asking " is this the best way?", "is it technically sound and efficient?", and "can I improve on this?" is very healthy.
In my opinion, the best way to go is probably a combination of a course and an apprenticeship. The course, in this case, would teach the technical aspects of the trade, in other words up-to-date
standards, materials knowledge, and methods, while providing some practise. Once there is a sound foundation to build upon, an apprenticeship would serve to hone the practical skills of the apprentice, all while he or she learns the quirks and "tricks" of the trade.
It's a bit like psychology; there are well over 300 academic schools of thought in psychology, but it's really hard to judge which is best. In fact, most of them are about equally efficient. Why? Because in the end, we're all human.
We all learn in different ways. I, for one, learn best from reading, and then applying and trying it in practise, all while critically examining what's happening. Others can only learn from doing things with their hands, and others learn from someone showing them.
A combination of all of the ways people learn, with some leeway for individual differances, is probably the best way to go. In my opinion atleast.