Instruction, with a good instructor, is valuable. You can learn from their expereince (read mistakes, incidents, etc..)
As someone who certifies instructors I tell prospective ones that being able to say "and when that happened to me ..." provides credibility.
Get experience between courses. Practice what you have learned.
Many experienced sailors are crappy teachers; they do not know how to reflect on their practice. For them it is natural and easy. Good instructors have both the experience and the ability to transfer their knowledge and skills to others.
ISPA Yachtmaster Offshore Instructor Evaluator
Sail Canada Advanced Cruising Instructor
IYT Yachtmaster Coastal Instructor
As I sail, I praise God, and care not. (Luke Foxe)