If you are asking questions, you are in my opinion on the right path. But honestly best make the character with personality, goals, dreams, morals (or lack there of) and write.
Honestly Im trans-masc and I more have my outlines and character's develop and I learn and figure out whether they are trans (As well as many other things) along the way Unless you are planning to write the struggles of a Trans person in depth whilst not being trans yourself (I don't recommend you do unless you have a trans co-writer looking over and writing), I would not worry too much.
I don't really have much to say on what I dislike to see since its more subjective than anything else. But I do like to see more gender non-conforming trans people (fem trans men and masc trans women/ or non-androginous enby's) and maybe just a character expressing more comfort with how they are. They can miserable with other things thou Im not that much an angel.
But either way your character is yours not mines, so their personality goals and wants are more up to you. Just do a little bit of research prior.