Personally, I feel romance in video-games are completely one-sided. Every romance subplot revolves around whatever baggage the love-interest has, with you fixing it like some quest. Romance really is the perfect opportunity to learn more about YOUR character as well.
Talk a bit, have a few laughs together (weird how player character usually never laughs), have philosophical discussions were you DON'T have to go with whatever they say like a lyrebird to advance the romance.
Another thing I should mention, is how relationships are constructed. The biggest gripe I have is how you finish a quest, click on the companion to talk to them, learn a bit of baggage until they tell you to "wait a bit before talking more", do another quest, rinse repeat. Even in Tyranny (a game I really loved!) most character interaction revolved around asking them questions for half an hour until all options were exhausted. It felt more like reading a book instead of getting to know my companions.
I liked how in BG2 the romance (or character interactions in general) proceeded at it's own pace. There was no "click to loveydovey". Happen upon a statue, and you may get into a conversation of history; walk through a graveyard, tell each other horror stories. This way getting to know your companion (romance or no) feels more genuine, and less like "ask 20 questions".
But I digress.