When I hear people talk about developing solid "fundamentals," what exactly does that mean? I'm just starting to learn about range balancing, GTO, having a gameplan going into a session, etc. So, what are these fundamentals and how do I begin learning them? I currently play 25nl and I do well, but I just feel like something is missing and that I'm not assessing certain situations properly.

This is my first post, so if I'm doing anything wrong please let me know!

Thanks!