Great tips from everyone.
I haven't read any cycling books. I taught Spinning classes for about 6 years & took those skills onto the road. And I loves me my hills! I'd rather climb than coast downhill (see the Tandem sub-forum for details).
But I digress...the two most valuable tips I learned in the studio that translate well onto the road are controlled breathing, and using the pull portion of the stroke over the push. Whether genetic or personal preference, it's easier for me to emphasize that upward pull (in any position) than the downward push.
That, and practice. Find a hill. Climb. Repeat. Enjoy.