Think about the poor mechanic that will need to get in there to repair something when it breaks!
AND IT WILL BREAK!!!
It all breaks
Also don't cheap out on materials, some cab are made with flimsy plastic that cracks way too easy. Not against plastic just when it is to flimsy.
Also think about fasteners, don't try to be too fancy or hide them. Just because it's simple to snap things together on the assembly line. Someone will need to remove panels to do repairs and those fancy clips and fasteners waste time and end up breaking.
I for one do not like all the fancy curved glass that is so popular these days. I know you make money selling that stuff but flat laminated glass is easy for a local glass shop to cut and install in less time than it takes to locate one of those curved windows, and heaven forbid that it gets broke in shipment! You can be the one to tell the boss that his 1/4 million dollar new machine is red tagged for safety because of a broken window that came in broke!
Make wear items like sliders and latches easy to buy and replace. Don't tell me I need to replace the door assembly because some little plastic guide wore out and now the window keeps falling out. Remember you are making cabs for machines that bounce around and get dirty, both cause wear so design for these conditions.
Make controls and switches easy to see and operated. Don't have a dozen identical rocker switches that one has to look directly at to see which one does what. Also remember many of the people running this equipment may be wearing gloves, heavy clothes in bad weather and hard hats due to safety regulations and heavy boots. What may seem simple while sitting at a computer drawing up a design in CAD can become a major safety problem while bouncing along an unimproved road in a construction site.
If you feel the need to use little pictographs/symbols to label controls so operators who, say might not speak English as their main language can run the machine put a decal somewhere easy to view that explains what that little picture with the waves in it and little thermometer is all about.
And yes to all the previous suggestions!
PS. Might be good to stop by a few construction sites and quarry operations and get a look at the operators you are designing these cabs for. Not sure about other places but around this area most are not exactly skinny little people. So seats need to be strong enough and access ways need to be wide enough for fast and safe access. It's easy to slide a seat ahead for the small guy but not always easy for Big Ed! Try to fit a 275++lb. line backer into some skid-steers!