I'm sure you will add your own. These are the ones I like to use:
1. Applying the whole body to keep strong air support (knees bent when above G top of the staff). See Ferguson clinic here: Maynard Ferguson 1977 clinic - YouTube At about 2:00 minutes in. Bends his knees more and arches his back the more energy demand is needed while ascending.
2. Not setting too tight of an embouchure. Especially true when using shallow lead trumpet mouthpieces like the 6a4A and such. If I'm consistently getting a fuzzy attack on a note like a High C# or so? I will think about setting for the B natural below. While this mostly applies to the first note of a phrase it can also help a string of notes. Especially those high notes which continue to need articulation.
3. Hitting the first note of a phrase just a hair early. Applies to the lead player. You're the first trumpet aren't you? Setting the tone, and phrase for the whole band. The rest of your ensemble looks to you for support (that's why they call it "lead"). If you play the first high note slightly early it can both help keep the rhythm (when playing in loud bands an articulation can tend to sound late) and aid accuracy. By hitting the note just a hair early you have a tad more time to lift it it to the correct partial if you're high or low.
Such as quickly bringing that High D down to the C when the C is the written note. Makes an attractive grace note feel.
4. Practicing Clarke Technical Studies up an octave slowly. Both tongued and not.
5. Practicing hitting a thousand G#'s at top of the treble clef staff every month. Why? Because this is the note most often cracked. While hardly an extreme register tone is still shows up almost as often as the High C. With both second and third valve pressed it requires the most tubing to blow through when above the staff. You can very easily hit the B Flat above or the F# below. This valve combination is the "fifth Position" relative to the valve slides put into use.
Trombonists don't have as much trouble with their corresponding note an octave below. Because they can use a "Short Third Position". Same as if we could use our first valve on the G# but we can't. Because it will sound way flat. Otherwise the trumpet tends to slot a lot better than the trombone. And the French Horn for that matter.
6. Avoidance of over training. Worried about the High D (or whatever note) at the out chorus and ending of the pops concert? yeah well don't practice the particular phrase it occurs in too much. Unless you have a well experienced embouchure and air support you'll just fry your chops days in advance. then flub not only that note but much of the whole concert.
7. The biggest mistake of lead playing (usually) is playing the correct note too soft. Often times you can pull a loud clam down or up to the proper note and still make it sound believable. Even to the trained ears in your band. Generally speaking the note not heard because it wasn't loud enough is the more profound mistake. Whereas even an outright clam might be forgivable if it is played solidly and in time.
Last but not least;
8. When in doubt? Play that high note a little louder. We don't often hear about the importance of being able to sustain good loud tone with plenty of endurance.
That's all I could think of for now.