Blueprints

@JennCsimmer, Sims 4 already has this feature, they are just called "rooms" and you can actually see them in 3d before placing them. You can also create and save your own, unlike TS3.

They basically work the same as blueprints.

As far as help and hints on building (and more), I recommend checking some of the links in this thread.

I think watching something visually is more helpful than just reading a bunch of articles about building. Go on YouTube and check out some builders. Some of my favorites are The Sim Supply, Deligracy, KateEmerald, LoveSimplySim, Simlicy, DevonBumpkin, and Lilsimsie.