Welcome to the Q&A Forum

I think that is not an question for a q&a Forum. Its basic SeoKnowledge

http://www.seomoz.org/learn-seo

If your content is public(crawlable). Its important that the dynamic content ist optimized automatically. (Title, Meta Description, Html Markup, and so on)

http://www.hobo-web.co.uk/uk-search-engine-market-share/

Bing has atm a market sharefe 4,25 % And the seo tactics that lead to success are nearly the same that help you with Google! Just read some beginner stuff  http://www.seomoz.org/beginners-guide-to-seo

Greets

I think its not worth to pay for any directory even not for Yahoo directory, Which would be the best one. With 600 Dollars you can do so much more than one directory link.

Creative viral Campaigns (I dont know how creative your niche is)

sponsorships of cool blogs of your niche (buy links)

get tons of content for your Site to promote and share ( hire hardworking indians)

I think there are many more ideas!