One tip I would have (being a novice Immortal Dynasty participant) is to not have a lot of harvesting plants at the start. For some people, that would seem obvious, but silly me didn't realise that it really eats away at time to harvest plants. My founder was out from dawn till 10pm most days harvesting! I can't believe I didn't think of it! Her poor husband was fatigued, hungry and smelly from looking after twins.
Now, she's maxed Gardening, and only grows special seeds that she finds, and the area covers only what one sprinkler can water. It's much faster, and now she can actually function as a regular Sim.
Another tip, which many people have mentioned, is plan! I found the template that Pam used to be very helpful.