Designer's Challenge- How do I become competent?

Hi, all!

I'm a Master Gardener without a good foundation of the principles of landscape design. In your opinions, what are the best 3 books I can get or top 3 things I can do to learn the basic principles of landscape design? I don't want landscapes I can "copy" to make a pretty garden because I adore unusual plants. I do, however, want to learn the best way to incorporate these unusual plants with my more common ones so that I have an attractive garden with year-long interest. Thanks for your help, as always!

Best,
Susie :)

BTW- I also posted this in the landscaper's forum. Thanks!