I think the most important choice is when you first meet Holly. Picking "I'm conflicted" should be the first step in opening something with her. (And doesn't hurt with Lexi.)
I think you can also get bonus points with Holly if you have a good "flirty" score, so try to favor those options if you can. Not sure if it's necessary though.
Otherwise, take conversation options and get a good look at her when she's smoking on the balcony. I think that should be enough.