My suggestion would be to first read stories that have trans characters written by trans people.

Read narratives. Listen to transmasculine folks. Google about cis people writing trans characters and the pitfalls that lie therein and the harm that can be done when cis narritives about trans people are lifted above those of trans people themselves.

There's a lot of variation between trans experiences and expression.

You haven't been here on AW all that long. Realize that you're asking for a lot of emotional labor. A lot. Without having given much to the community here.

I *have* beta-read a novel specifically for non-binary rep (I'm non-binary transmasculine), but I only did it because I knew, had conversed with quite a bit, and admired the hell out of the author. The author's works that I'd already read have wonderful and sensitive queer rep. I trusted the author would approach an NB character with the same nuance that they already had displayed--so I felt *safe* in reading the work. I also knew the author would take my suggestions to heart because we talk about queer rep all the time.

So basically, do your homework, interact with folks on a personal level and build up some friendships here before asking for extremely personal information.