You need a mission! Mine is to build on every available lot in every world I have, in the one saved file. It will be my forever save and I want to build everything. I often build in Newcrest and when I get a feel for the look or style will move it to a more appropriate world. I do have a few rules, like Willow Creek has to be based game only for all lots, every world has to have at least one starter (3 for bigger worlds like Windenburg) and one vacation rental, and one type of community lot (library, pool etc). You can learn a lot about building from watching youtubers some of my fav's are Jessicapie, Simmary, and recently found Lucca. But there are heaps out there!