I'm 6'6, and think the cabinet is about the perfect height, so personally, I wouldn't stray from OND's dimensions there.
A few mistakes....biggest was just calculating angles correctly. IE, measuring one of the angles to be say 70 degress, knowing that each board needed to be cut at 35 degrees, but instead, cutting to 25. Huge gotcha that's obvious but very easy to make.
Some other mistakes...I like to leave just enough gap between the marquee and the upper panel to slide plexi between to help hold it. The first several cabinets didn't leave enough gap when you slop a bit of paint in there, so I ended up having to razor blade enough room....just time consuming and frustrating
Here's one that's not necessarily a mistake, but took me 5 finished cabinets, and halfway thorugh #6/7/8 to realize...when I glue the batons (sp?) inside, I was gluing/screwing. Someone mentioned using a nailgun here, and that started saving me a ton of extra time...if you have a finish nailer, use it!