One of the things I found confusing when I first started was how to change display tree on the fly, and the answer was to create most of the display tree, but leave hooks in place (display box object variables) that I could append to later on. So my suggestion would be to reinforce the use of append() and prepend() in some of the example scripts, maybe based on if() statements.
Also, in a JMP training class at the 2014 summit, I think it was Xan that mentioned that prepend is faster than append, so for large display trees or iterations of parameters, it is faster to build the display tree backwards. I haven't tested this out. It's easier for me to think forwards and I've never gotten around to re-writing the scripts that would benefit from this.
Along those lines (not just display boxes) but tips on making scripts run faster would be really appreciated.
I also use the page break feature between parameters' outline boxes so pdf reports look nice. Otherwise the previous parameter's outline box shows up on the subsequent page.
Not sure I actually answered your question, so here another, checkboxes. For some reason I tend to forget that checkboxes can be used as a list, and I tend to use them as 1 box. So when I want to set a default as "set (n, 1)", it confuses me until I remember that set(1) also works. And also this needs to be placed after the the display tree or within a script of one of the display tree functions (script argument).