Someone once asked me what's the first thing I would like for people to learn. After thinking about it for a couple of days I told them awareness. It seems to me that most people ignore or simply don't see the things they should be aware of and are aware of things they probably should ignore. Too often people get tunnel vision on something like the headstall has two holes showing at the top on the left side and only one on the right, but they never notice the horse bulging his ribs to the inside every time they ask the horse to canter on a right lead. One hole on one side and two on the other is really not that important but an ill-prepared, out of balance horse is. This is one example I've seen over and over where people need to think and be aware of what matters.
Your horse is always thinking and is very very aware of his surroundings. We owe it to him to do the same. Think about what's going on around you. Think about how your horse is responding. Think about how you can be aware of the relationship you have with your horse and how this moment can build that relationship up or erode it away. Think about how things are shaping up for you and your horse. Think about becoming aware of everything you possibly can so you limit the number of "surprises" you have with your horse.
When it comes to awareness be like Winnie the Pooh, "Think it over, think it under."