I actually renovate lots as I go along, instead of fixing them all up at the start. I add or remove objects as the households' needs demand it, or if I think a room looks better with a yellow instead of a blue wall, etc. I'm not much of a builder, so I use the premade lots, and don't change the exteriors much, but the interiors will eventually become unrecognizable from the original lot. Community lots I do fix up at the beginning, now I have renovated versions of the big parks in my library to just place when I start a new save, since I tend to start new games ever time I sneeze.
Actual rotation, depends on what life span I chose. If I have a lot of households, it's normal & I rotate on a weekly (sim time) basis, usually Sunday to Sunday, switching at around 7 am. If it's only a few, then I go "annual", 4 weeks from spring through winter, on long lifespan. Pregnancies are halted in the last 4 days of the schedule, except in the case of alien abductions, I like to name the babies myself instead of letting the game do it.
When I create sims I usually start with young married couples, and let their offspring branch out from there. Unless it's a premade or single family save, I only allow my sims to partner up with each other, NPCs are seldom brought into the picture. Right now I am actually playing a single family, I will start rotating when the kids grow up & move out. I'm thinking about adding a couple other families to it though.
Other than that I don't really have any rules or tips. I keep track of them pretty simply on a couple notepad documents, one with the rotation order, one with potential baby & new family names, and with various plans for each family & future potential partners. Nothing fancy.
