Think psychedelic design. Despite the proliferation of advice, even from staidly gray outfits such as the Wall Street Journal, many sites look like drug-induced marvels of flashing lights and confusion. Providing too much information on the opening page deters users. Fewer options and a simple design are key. Build it to run slowly.
Sites run slowly as a side effect of cluttered designs and flashy stuff.
They also creep along if they're overburdened by too much unpredicted traffic. Don't bother offering a search function. Many companies require users to go through a confounding number of twists and turns to find a product on the companies' Web sites. However, everyone knows what the Search button means. The worst sin in building an e-commerce site is not providing a solid search capability.