Case Building

Here are a few things that I've found to be the most difficult to get right without spending an inordinate amount of time:

The valence

The valence is where the top hand bottom halves of a case meet. The two halves  can just be let to butt against each other, but everything has to line up absolutely perfectly for that to work, and it doesn't provide any kind of seal or reinforcement. A good valence aligns the two halves, seals the case from the elements, and strengthens the case walls.