There are many, many aspects of trumpet playing that must work in sync for an ideal sound to be produced. However, we cannot attempt to think of all of them at once. For me, it is easy to slip into an evaluative mindset, and react to how I sound. Rather, I am seeking to focus on one aspect of the playing process, in the moment. I might be playing a solo and focus on Ease of Flow. I might be playing stamp, and focus on watching my fingers really press the valves down all the way. I might be in orchestra rehearsal (already knowing the music cold), and focus on taking a full breath at every phrase point.
The challenge is that we must trust that the other aspects are in place. In order for ease of flow to happen, we really need to be taking a full breath. However, there is freedom in continuing to return to this one idea throughout a section of our practice or period of time. We must develop these skills as part of the whole, not to the exclusion of our other habits, but as the way to develop these habits overtime. It seems contradictory, but the main goal for me is to not be results oriented. Let's stay in the present by focusing on the process.