Do what Archie Moore did- fight a lot of rounds with very good fighters. If you are very lucky you might find a trainer- a teacher- that will start you down the road of being thoughtful and observant. He would get you to notice things that some fighters do to tip off the punch they are about to throw. He would teach you to pay attention to where your feet are and the value of small movements, where to put your head inside. Nobody can possibly prepare you for every eventuality in the ring but, if you are lucky, you will find somebody that can prepare you for several while teaching you how to learn from what you are seeing when you spar and fight.
Other than sparring and learning your options from different positions, actively watching film study or fights in slow motion can be great. When someone gets clipped or knocked out, try and put into context what led up to that as well as the positional openings that allowed it to happen. Watching great fighters and learning how they fight is great too. In the end its all about time and effort. On top of that, defensive sparring is great because it helps you focus on developing your defense, this is where you get somebody u trust to hit you a certain amount (can just be 30 percent and then go up to 70 when you have a fight or spar coming up, get them to throw those techniques that u know how to defend at u and hold the pads for them. Itll do wonders for improving your fight iq
Two youtube channels I recommend are better boxing and skillr boxing, they break it down super in depth and slow it down and draw on top of the visuals. It can be also really fun to learn this way by learning the styles of your favorite fighters!
Combination of harder and more relaxed freestyle sparring. Sparring with limitations (stay at x distance, only use this hand/punch, only use this kind of defense) etc. These are a couple of things that helped me to think outside of the box and explore things outside of my comfort zone.
