I have written from both binary genders and I attempt to write in the area in between them. I'm not sure how successful I am at the non-binary, but in male and female I find a voice for the character and follow it through to the end.

I write stronger from a female perspective many times, but there are a few times that I can really find that male character. You already write male characters from the outside. You can slowly peep into their heads and work out the inner parts as you go. Take it slow and keep trying, and get feedback when you can from males (or whatever viewpoint is out of your comfort zone).

I always find that helps, to get that feedback and understand if my perspective is realistic. Also, study the guys around you. See if you can puzzle though their motives to make your characters stronger. You can also try to guess their actions in advance. None of them will be the character, but understanding men is the first step to creating your own male character from scratch.

And good luck!!