Well not too much of SEO. As per my experience I do really believe that Content is King and for best results the best practise is to provide great content on your custom website design page. And for back-links generation you may definitely use such techniques like Forum Posting and Blog Commenting.
I am agree with the above said statement that SEO, and good content is necessary to get traffic. the creative website design is also important to catch the eyes of a person. The feature of your product or service is must be in your website because the visitor easily searches the products by the feature.
Yes, a good web design is helpful for getting more traffic to your website. If a user will get proper niche related content, headers etc..... Then more user wants to visit your website. It is a shortcut to attract visitors and also good to increase your website quality.