There are a lot of style to build in! You can use wooden items and walls to build Medieval,Metal walls and loads of glass walls and roofs to build Sci-Fi/Futuristic, Or just use bricks to build in the time of now! And yes! You can combine styles or make your own!
We will start with the easy styles, and how lower the number how easier!
1. Roman. Roman is the hardest because it has small changes in pillars and stuff!
2. Medieval. Medieval can be hard because almost everything is made out of wood, and you have to show the differences! And yes, you also have castles from bricks, BUT you use brick walls so I will count it as Time Of Now style.
3. Sci-Fi/Futuristic. This isn't the easiest style because it hasn't got any sloped walls.
4. Time Of Now style. (TONs) This is the easiest because this is very simple and has everything you need!
5. Your own style. I put in this one because it hasn't got any rules but I official don't count it because much pro's (like me) have very strict or hard own styles.