Learning how to add nodes to change a material. Using different nodes to make a brick texture. Using normal maps to add details. Adding mortar. Creating the color for the bricks.
Learning to work with planar mapping. Working with cylindrical mapping. Working with automatic UVs and manipulating them. Using multiple different types of projections on one object. I learned how to transfer one UV set to another model. I learned the importance of separating UV shells into different layouts for higher rez.