I certainly agree with all the resources posted above - they are extremely helpful with getting started on web design and understanding the latest trends.
But one resource I find indispensible is the actual process of designing for clients! Understanding client requirements and brainstorming on the appropriate design elements is an aspect of web design that can only get better with more hands-on experience.
Another way to learn more about web development is to be involved in the web design community, be it online forums or local meet-ups. Exchanging useful tips and experience with like-minded people is a sure way to keep yourself updated and motivated in the niche area of web design.