If you go through this site to buy anything on Amazon.com, BYB gets a small finders fee that helps pay for the expense of the site. At no extra cost to you.
A good compass is arguably the most important piece of sea kayak equipment there is. My favorite is the Ritchie Kayaker Compass. Mount it where you can reach it to adjust your bearings on the bezel, just past your oriented chart and let the fog roll in.
Another favorite item that corresponds to the compass is: Fundamentals of Kayak Navigation by David Burch:
This classic is packed with practical information. You will find yourself returning to this book frequently as you increase your navigation skills. Advanced skills like compensating for drift are covered in detail.