Not sure.......yet, but what i do know is what makes a not-so-good design. I think that any person with any hint of artistic ability can label certain components of a site to be "bad". Huge text, random colors, "boring", mismatching items, the list could go on forever. But what it all boils down to is one thing: Items that do not have any purpose in the design.
Like I said, anyone with a hint of artistic ability (like me) can match colors and create blocks of text and ultimately create a nice layout, but does the layout have a "why" to it? What's the importance of aligning text a certain way, why is item 1 this color, but item 2 that color? Why is this content divided the way it is? I've been interning now for a little over a month now and I realize how much of an amateur I really am......a horribly, designed-challenged amateur.
But recently, an unexpected source helped put it into perspective. It was actually a sales man who was having a talk with my boss. As my boss was talking the salesman would ask well why did you do that? Who is it for? Who's gonna use it? Who's your target? And I think these points describe exactly what a web designer should be thinking, along with how do I make this eye apealling and effective. And once you answer all of those questions, everything in the design has a purpose and it's not just....there.