Read everything on Jakob Nielsen's blog about Usability: http://useit.com/
http://www.amazon.com/Think-Common-Sense-Approach-Usability/...
It's more of a usability book, but it covers some visual aspects to design. Beyond that it comes down to reading, practicing, critiquing and being critiqued. Any time you visit a new website think to yourself: what looks good, what looks bad, what is intuitive, and what doesn't make sense.
Here are the resources I drilled out of the threads I came across:
Type: http://www.amazon.com/Logo-Lettering-Bible-Leslie-Cabarga/dp... http://www.amazon.com/Graphic-Design-Manual-Principles-Pract... http://www.amazon.com/Elements-Typographic-Style-Robert-Brin... http://www.amazon.com/Non-Designers-Design-Book-Typographic-...
Usability: http://www.amazon.com/Think-Common-Sense-Approach-Usability/...
Design: http://www.amazon.com/gp/product/1592532616?ie=UTF8&tag=... http://www.amazon.com/gp/product/1592533485?ie=UTF8&tag=... http://www.amazon.com/gp/product/159253192X?ie=UTF8&tag=... http://www.amazon.com/gp/product/1592532349?ie=UTF8&tag=...
Web Design: http://www.amazon.com/gp/product/0975841963?ie=UTF8&tag=... http://www.amazon.com/gp/product/032145345X?ie=UTF8&tag=... http://www.amazon.com/gp/product/1847192505?ie=UTF8&tag=... http://www.amazon.com/gp/product/0735712069?ie=UTF8&tag=...
Sites: http://dribbble.com/ http://www.deviantart.com http://forrst.com/ http://lookslikegooddesign.com/ http://webtypography.net/toc/ http://ui-patterns.com/
It's a quick read that will give you tons of "A ha!" moments.