on writing well

This is one of my newest used bookstore purchases. It's a first edition, published in 1976, and since a few revisions have been published, including a 30th anniversary edition a few years ago. Some examples are outdated, but that only makes the read more fun. I can feel good things coming from my study of his principles already.

Here are a few notes so far:

• warmth and humanity are what all good writing should express
• learn to control your material (this is the basis for the whole book)
• care deeply about words
• simplify; cut out the clutter
• you will learn to write by writing
• unity of thought and style is important

I'd love to hear your thoughts. What is your favorite manual for what you're learning? And what are the most important principles for your craft that you've learned so far? Or are learning now?