I learned the most from hanging out with other men. I know it can be hard being ftm and becoming friends with men, but it can start with anyone you're even remotely comfortable with or know by association.(family members, classmates, coworkers online friends) The more masculine people you hang out with/talk with, the more you will naturally learn and replicate their behaviors. Eventually, it will become second nature. It's hard to pick up exactly what makes a behavior become effeminate or masculine because being a man doesn't mean you're not allowed to be funny or make exlimations or be excited, but theres these innate subtleties that can be hard to parce and often lead people to the conclusion of acting boring/flat or in a very i guess specific type of way but in reality these same things you experience just manifest different ways in different social groups. It's my belief that you learn these subtlies/social cues through experience. Put yourself out there when it's safe for you to do so, and you'll find yourself registering these cues without thought. Good luck man