All the time. It's worse around other guys, but just seeing any part of my body is a reminder (small frame, light body hair, etc.). Stuff that helps me:
Remembering there are many men with similar builds/shorter than me/can't grow facial hair due to genetics/etc., trans and cis. "It's not just me, lots of guys have [trait]."
Focusing on the future, after surgery and time on testosterone. "It won't always be this bad."
Concentrating on the things about myself I consider positive, or focusing on what I can change now, not what can't be changed yet/ever. Working out on a regular basis. Thinking about what kind of man I want to be, and remembering how many important aspects of that aren't even physical.