Big upvote for Edward Tufte. If you style yourself as a hardcore engineer, start with his book Visual Display of Quantitative Information. I'm away from my copy, but as I recall, John Tukey reviewed the manuscript. (http://en.wikipedia.org/wiki/John_Tukey)
Tufte is extraordinarily dry for someone new to design. Great recommendation though but it would be like going to Saul Bass and asking him how to draw a "stick man."
I would start by using grid based layouts and study those who have used them. Start with wikipedia article on the
I don't really think Tufte is appropriate for a design discussion. He's a mediocre charts and graphs guy (he's no Cleveland, Tukey, or Few; if you go to one of his talks he basically reads directly from his books and makes fun of PowerPoint.)
Design is more the arena of people like Dieter Rams. You can't design an application, a chair, or a home with sparklines.
