Do you do the same thing as me, and make them a household from the start?
I have all kinds of households from whole families to singles created from the start (I play rotationally)
Do you create your potential love interest and have them move into their own home? If so, how do you get them to eventually meet?
Yes, if I create two singles I want to become a couple I usually establish each life first, have them have a home, a job, friends and/or familie and all that.
They meet through different ways, some meet through mutual friends, one of my sims is a vet and her soon-to-be girlfriend has a cat, so I just had to wait till she came to the clinic, another couple met through their mothers (who are best friends), one couple met in Uni, but sometimes they just run into each other in venues (clubs, bars, parks...whathaveyou).
I like the intial meeting to be organic and fit the characters.
Do you let the game determine who your sim will fall in love with?
no, I only play self created sims and I don't go for NPCs or premades/townies for serious relationships, however I don't plan each relationship from the start, I have some single sims with no romantical plans and if they run into each other and get along by accident who knows...