I started reading some blogs and watching how-to videos to try to get better. I read that trying to copy the kind of art that you eventually want to produce is really good practice. Here's my "practice" of one of the simpler kinds of art I like. I didn't even finish the clouds. I practiced more shading, but I still need some help with perspective, colors and rendering.
I aspire to paint images like this (go view it in large!):
New goal: Draw Everyday!
Cool stuff to look at:You can follow my favorites on Deviant Art here.
My favorite video series on digital painting and drawing in general is Ctrl+Paint
I follow the Muddy Colors and Painting till Death! blogs and read the Imagine FX magazine.
I'm a fan of White Cloud Worlds, a series of published works from New Zealand.
I got really into Strip Search earlier this year, and now I follow a lot of those artists' works - The Cloud Factory being my favorite.