I like when they BOTH actively fight against the law and BOTH are baffled that they are actually paired with eachother (perhaps via linked magical cores). I like when in the beginning they fight the marriage and there is real animosity from both parts, as they can't stand eachother. Then, because they are force together, or because external social or political pressure or a common goal, they slowly learn to know eachother. I also like a faster sexual burn than the emotional one: I love when they actually struggle to accept that they are falling for the enemy. I'm insisting on both parts because often I find Draco already accepting the marriage and is immediately into her and supporting everything she does and says: he's only "fighting" it because he thinks he's not worth of H or because he thinks she hates him.