As we know that a web site design and layout gives first impression of any site. If your site is too fancy and regular net surfers will just reach on those sites only and will come out even without pressing a single click.
Now days, Search Engines are very smart enough but after all they are software and not human being who will read the content of their interest. If your site is too complicated then Search Engine would not be able to parse the content of your site properly and finally indexing would not be efficient which will give in a low rank.
The real page content should have a keyword density of about 10% and weigh in at about 200 words – as per SEO experts, keyword density should be 5% but some say it should be 20%. 10%
While designing a web page, few guidelines should be considered
1. Have more text content than HTML elements.
2. No frames. They are the enemies of Search Engines
3. Avoid ads if possible. Because most of the ads uses Java Script which is not advised to be used.
5. Avoid unnecessary directories. Keep your files as close to the root
6. Avoid fancy stuff (Flash, Splash, Animated Gifs, Rollovers etc.) unless absolutely necessary.