Seo effects every single aspect to your page. If you head over to massivemarketers which is one of my favorite blogs to visit. They have a
seo section in their blog which should help you. What I always try to do with my sites is to make the title and description 100% relavent to the page at hand. I try to make the keywords no less the 75% keeping all my longtailed keywords at a minimum of 2% and no more then 4% keyword density is another huge factor on
seo.