On this week's Best of The Build Show, Lydia explains the fundamentals of properly filling flat drywall joints. She covers why allowing tape and mud to fully dry is essential, how bevels work, and how to avoid overfilling that leads to visible wall humps. Lydia demonstrates correct knife technique, feathering edges, and maintaining tight, even coats. She also explains coat sequencing, shrinkage, sanding between coats, and best practices for clean, professional results.