Congrats on the courage to push yourself and your trumpet playing. I'm making some assumptions (probably poor ones so apologies in advance if so) on your length of playing given your post about your playing knowledge. Proper form may help. This means, keeping your elbows out, stand (or sit) tall, shoulders back. Now the best tip I can offer, use your diaphragm. If you aren't sure how to do that. Place your hand on your stomach. Now breath in making your stomach expand first, then your lungs. This will roughly double the air you breathe in. More importantly, you'll be able to deliver the air more powerfully using the strength of your diaphragm. Practice breathing like this, hopefully it'll help.
Here's a guide I found on properly holding the trumpet or flugelhorn. Good luck with your playing !
Re: Would you run outta` breath? 05:25 on Sunday, December 22, 2019
I have a fair idea the original poster does not play the trumpet at all. He's composed or arranged some music that involves the trumpet and wants to know if it's reasonably playable. I tried clicking on his link, and it didn't work. In any case, my advice to him is first read about the trumpet in a good orchestration text, or better, several good orchestration texts. I recommend (in this order) Walter Piston's, Cecil Forsyth's, and Kent Kennon's. Then find a trumpet player and ask him to try to sight-read the part. Don't just rely on what the trumpet player says; have him try the part in front of you and listen carefully to the result. Failing this, take up the trumpet yourself. If you can't do any of these things, don't write for trumpet. In general, how long a trumpet can go without taking a breath or hurting his lip depends on how good the trumpet player is and how high the part is, but there's no firm rule.