Roothost is on the right track.
You need to have a solid foundation in design principles. Design isn't just painting a pretty picture, it's method of communication. Once you understand the basic language of design, it's much easier to communicate through it.
Try reading up on basics like line, shape, color, gestalt, dominance, balance, etc. Understand how things work. If I remember correctly
This Book does a pretty good job of covering the basics in a web design context. It'
s certainly not a complete tome on the subject but it's a good starting point.
After you have the basics down, I'd start by sketching. Sketch up a dozen ideas for the page you are working on. Then figure out what works and what doesn't. Throw these sketches away and start over, pulling the best parts from each sketch. Once you have something you are truly happy with, bring it into Photoshop or whatever you use for a graphics editor.
Or, you can try going right into HTML5/CSS3 instead. That works better for some people so it's worth trying out.