what is the best layout for an affiliate website for good seo results ? do I need to have splash pages that lead to my affiliate pages with a no follow ? is it possible to rank an affiliate site even?
There is no "Best". You "Optimize" the site the same way you optimize any content. Google looks at content and links. Then they measure time on site, age of domain, and a host of other user behavior factors. It doesn't matter if you are an affiliate site or not. In my own personal experience and I've been at this a very long time... it is no more difficult to rank an affiliate site than any other site. While I can not prove it matters... there seems to be evidence to suggest that you should be tagging your affiliate links with nofollow. There is no way to hurt yourself doing this and a possible benefit. Google is very aware of the Affiliate Networks... and they do NOT increase the ranking of those links... if they did the Affiliate Sites would have an unfair advantage.