Great thread, I'm getting a lot of ideas!
I just started playing Sims4 in May or June and none of my sims has hooked up yet, although I have several couples in the "get to know you" stage. Usually I get impatient and give up too quickly but this time I have certain plans in mind so things should go better. My main problem seems to be the computer, if there is a computer in the house the computer owner will NOT stop playing on it, and it's hard to romance someone who is glued to the screen. I lock the computer for everyone but the homeowner/roomie because it is infuriating when someone comes over and ignores the host in order to play on their computer. Once I start relationship building in earnest I may just sell their computers till coupledom is achieved.
When I played Sims 2 eons ago I did whatever felt right for the story I was playing. I would date sims and see who got along best before marrying them off, create couples, break them up, or create the perfect pair and have them meet. Sometimes the perfect pair wouldn't get along, in which case they usually wound up with a random Townie.