A good strategy early on to ensure there's always a potential spouse for your heirs is to move in a vampire and have them turn your favorite pre-mades on free days. Ideally get your controlled sim to at least vamp lore level 3 so you can buy plasma packs for the vamp. In my experience vamp sims don't feed on human sims autonomously unless they get to super low thirst, but if you give them plasma packs they will autonomously use them. And if you're concerned about vamp heirs due to the -10 vamp penalty, don't be. VL levels fast and can be maxed in a couple of days, so if you do have a vamp heir you should easily be able to get them cured by the time they begin accumulating points.
It's also notable that sims with a spouse and/or kids do become eligible spouses if turned but not the rest of their family once the spouse and/or kids die, so if you wanted someone to wed, say, Bella Goth, they can this way.
If you have Parenthood, the influence ability is a great way to indirectly control your kids, such as making them do homework. Getting an A is a lot easier if you have this pack.
Another tip: a good way to get quick cash is to move in a homeless sim that lives alone for a nice 20k simoleons. Ideally they'll be elders too so they'll die soon and free up the space they took so that you can move in even more homeless sims.