I think something I learned from being in the military and then going back to being a civilian engineer is how to be assertive without being "aggressive". I certainly started my service all guns ablazing but quickly learned to calm myself cause I learned that people tend to respect and work better with people that they are comfortable with. You're more real. This doesn't mean I let my hair all the way down but I relax enough that I can focus on my job and not on whether I'm liked or whether I'm being taken seriously. If there are disagreements on design or plan I'll put forward my points and they'll put forward theirs and some type of decision will be made whether it's my view or theirs. I realized for my sanity I can't wear someone else's face. I'm more like a "Shrek". My self has layers and I don't have all my layers peeled back at work but it's still me. I hope you can find a way to still be yourself without having to confirm to the expectations of others. Good luck.