I've been approaching it in terms of visitor archetypes, like in the case just now of a person who doesn't know what you're about, or someone looking for the spec, etc. What questions do they have, and can it be answered easily.

I also think being deliberate about where you draw attention to is big. Colors, images, do they serve a function or are they merely to fulfill an aesthetic? Regardless of why you put them there, for better or worse, they will draw the eyes of your visitors. Possibly away from what they are looking for.