When you make a web project (if new or a restyling) the design become so important indipendently from the kind of web site (blog, portal, e-commerce, community, etc…), from the technology used (HTML, Flash, etc…) or if you use or don’t use templates and developing tools (Photoshop, web editors, etc…)
An efficient web design leads to a web site success.
A starting point is design on paper the layout as you plan, also taking inspiration from other sites.
In that aspect you also must consider the choose of color schemes that don’t must hurt (there are sites to generate these patterns and to see the created patters by other users).
Another element you must consider is typography, choose the fonts to use and their styles. Generally is recommanded to use safe web fonts, that theorically must be common between all OS and their versions. Thanks to browser’s evolution and to technologies used in web you can also use the CSS property called font-face to easily include alternative fonts to render your web site more “customized”. Google web fonts are very popular.
Both if you choose a minimalistic or more stylish look the web site don’t must be too heavy to load (as you know it’s also bad for SEO).
An element not much considered is the use of advertising (if used): too much or intrusive can put a strain on web design, so moderate it and place it correctly in your layout.
Lastly for an optimal web design the web site should be the most compatible with various browsers and devices used (for example mobile devices) and with various screen resolutions.