I have to say, like everything, if you don't have the right tools, or even know how to use them, your life can be difficult. It's why you hire people.
Another aspect is you need to know what it is you're looking at expecially when you look at examples. That means not just knowing how it was placed on the page or what the file type is, but what effort was required to build it.
Those are pretty much the ground rules - take it from someone who studied art and design and spent 7 years as an art director.
if you are looking at a png image for example, was that png image generated from a vector program like Adobe illustrator or Inkscape, or was it a sample from a bigger image or has it been put together pixel-by-pixel in photoshop, or was it sketched out by someone and scanned or is it a photograph? What part do gradients, layers, blending media play in it? What possibilitites does CSS3 give us to reproduce some common effects... I could go on. A good artist will know the answer to that within a few seconds.
The best thing I could recommend is get yourself a friend who does that stuff for a living, then get them excited in what you are doing. Then, drop the question...