Keep it simple: In general, ...

Keep it simple: In general, interfaces should use simple geometric forms, minimal contours, and a restricted color palette comprised primarily of less-saturated or neutral colors balanced with a few high contrast accent colors that emphasize important information. Typography should not vary widely in an interface.
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 Alan Cooper

Quotes from the same author

Because computers have memories, we imagine that they must be something like our human memories, but that is simply not true. Computer memories work in a manner alien to human memories. My memory lets me recognize the faces of my friends, whereas my own computer never even recognizes me. My computer's memory stores a million phone numbers with perfect accuracy, but I have to stop and think to recall my own.
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 Alan Cooper
Usability methods are like sandpapering a chair. If you are making a chair, the sandpaper can make it smoother. But no amount of sandpaper will turn a chair into a table.
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 Alan Cooper
Computers no longer interface with humans--they interact, and the interaction will become steadily deeper, more subtle, and more crucial to our collective sanity and ultimate survival.
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 Alan Cooper