Stephen Few's book, Information Dashboard Design, is about the design industry bible on the subject. (His other books are supposedly good, too.)

As many of the other comments in here have noted, the design of a good dashboard is often "don't design one, you need something else."

There are heuristics in the piece which are useful.

The most critical piece though is: is the data being presented actionable?

Can I do something with it, do I need to do something with it, does it tell me when I need to do something?

Think of the most common dashboard: a car.

It tells you how fast you're going (speedometer), how much fuel you've got, how far you've gone (trip/odometer). Indicators for services or features enabled (lights, hi-beams, turn indicators, hazards). Problems (engine temp, problem lights). Maybe a tach. Automatic transmission indicator, if applicable.

Other chrome is possible: outside temps, compass, and comfort/environment controls (heat/AC, sound system).

But essentially it's a few crucial indicators which either give you current status or tell you there's a problem.

It's not a bad model to start with.