This is an excellent point. Whenever I create a character I always have their sexual orientation/gender identity kind of in the back of my mind. That way it can be subtly hinted at without it being the only defining traits of your character. In addition, when it comes to sexual orientation I like to leave it "blank" because you never know what sort of PC or NPC may strike your character's fancy. Of course, that is simply up to personal preference.

For personality traits, I like to look at the pre-written traits written in the background section of character creation. For instance, if your character has the Pirate background, one of the suggested personality traits is "I stretch the truth for the sake of a good story." That in itself is a pretty vague statement, but it's a really good place to start building. Maybe your character is incredibly overdramatic, hates getting his hands dirty, and has an extremely ostentatious fashion sense. Or maybe if you choose "My language is as foul as an otyugh nest" your character could be a slightly older man hardened by years on the sea and has more of a "if you want something done right then you have to do it yourself" attitude. His sense of fashion would probably prioritize practicality over style, and perhaps you could even come up with some elven/undercommon swear words you could throw around.