Simple and focused. As much as possible, opt for lesser elements, clearer divisions, fewer columns, and less clutter. Simplicity is the key when it comes to these kinds of websites. Simple layouts that are focused on the important parts of its website are very much needed in the industry of web advertising, probably because It directs people to the more important matters in their sites. Minimalism works great for refreshing eyes that have become weighed down by websites with heavy garish colors and an overload of elements. Also, if you are using multiply columns or frame, try to create focus on the most integral part by harmonizing the color scheme, images, fonts and whole flow of the layout.
Bright and bold. Making use of bright and cheery colors often do the job for many websites. These colors are the ones that scream of energy and freshness. Warm hues may also be used, but in bright tones. Another thing would be to use dark rich colors. The reason behind this is that the colors are like the petals of a flower; they are the ones who urge the website viewer to come closer and take a peek at what their website has to offer. Remember that good contrast is the key; now is the time to take advantage of different color schemes such as complementary, triad, split-complementary, etc. Study your elementary color wheel, or better yet, try out Adobe's nifty color-matching program called "Kuler", or view the Sitegrinder gallery to get more ideas.
Defined logos, icons and clean, sleek graphics. Take a look at today's popular website and one thing you'll notice is that few use the fade effect so used and abused in the days past. A clean-edge logo looks more solid, and will generally look the same even if you have it put up or printed in other mediums. One that utilizes a fade-effect will have to compromise somewhere. As always, keep in mind that your logo should be able to represent you company well, first and foremost.
Critical use of reflections and gradients. When used sparingly, and in the right places, reflections and gradients maximize the sleek and finished look of your site. Be careful in overusing them, as the effect desired might just backfire. Try viewing things like his in Sitegrinder to see whether the reflections are too much or not.