Right. The general idea is: the bigger the font size, the more people will notice it, so make the irrelevant stuff small and the attention-grabbing stuff big. As to colors, I just saw something someone else posted that can help you develop a coherent color scheme:
http://www.techiemania.com/5-awesome-free-tools-to-help-you-...
And another article with good design pointers submitted to HN:
As to the logo, the same ideas apply: more whitespace between the title, tagline and "beta", vary the font faces to provide contrast, and try using contrasting primary colors to make it a bit more dynamic.