Welcome to the forums.
The new building sites have definitely dried up, which has somewhat flooded the domestic market with tilers.
However a reputable tiler with contacts is still busy. Loads of extensions, bathroom & kitchen re-furbs on as people are spending money on their own pad rather than moving house. Its not all doom and gloom. But be careful, its a big step.
As for courses, you need to learn all the basics, speed and dealing with complicated issues comes with experience (and asking questions on here). So pick a course right for you from all the feedback in the courses review threads.
Good luck