more or less, all the search engines have the same ranking factors, but for yahoo particularly, Onsite optimization is quite important. Title tag, meta description and keyword tag way more important in case yahoo, than it is for google (Google gives a bit lesser importance to such onsite factors). Also, directory submissions are quite important for yahoo.
All sites above me are affiliate sites. I read a post about yahoo filtering affiliate sites, but in my sector top10 are all kinds of affiliates.The most frustrating thing is, that top10 is total spam.
Do Article Submissions, Blog posting, forums, Bookmarking, press release and yahoo answers and submit your website in yahoo directory
Its same as other search engine. You must do seo like on page and also off page. But you must submit your site on yahoo directory.