A nice blend of experience and theory is what you want and on the plus side you can substitute more experience for less theory. But, you'll learn a lot faster and have less issues if you get some theory in there as well. This is still my most preferred sailing book:
Amazon.com: The Annapolis Book of Seamanship, 3rd Edition Revised (9780684854205): John Rousmaniere, Mark Smith: Books
Read up on something, then try to practice it on the
water. When you have a problem on the
water, go home and read up on what was happening, and learn how to address it. Just keep going through that cycle because it's essentially what you'll be doing as long as you're sailing (predicated that you want to continue to improve).
There are a lot of smart mariners out there who've taken the time to write down some un-alterable rules of seamanship and sailing. It will save you a ton of time to learn them. Things you might have been able to get away with in 15 knots will becomes problems at 30 knots and tear your rig off at 45 knots.
I'd *really* recommend using small boats.
Learning on how to sail a
dinghy will teach you
boat handling skills that are abstracted away from you on larger boats.
I actually made a blog post and video about this very topic last summer.
Rebel Heart - Sailing, cruising, liveaboard blog and website - Eric's Blog - why you should learn to sail on a*dinghy