as for me, optimizing for yahoo is just like the same as optimizing for google. follow quality guidelines of google and soon you will also get good results from yahoo

Yahoo gives more importance to keyword proxaimity in content (Title, Meta, Body, Alt etc), also give special previlage to keyword rich domains.

If you optimize your site in google you also getting ranking in yahoo

There are no different into optimize...

but i think yahoo like old and big sites but google like new things even not big sites.

You should concern the keywords and built quality backlinks.

The factors are common for both google & yahoo except the following points - yahoo answer
- keyword oriented domain
- submission in yahoo directory.

from my experience yahoo gives more consideration to meta keywords and meta description than google, other than that it's preety similar

A good SEO job done for Google will also reflect on yahoo.

You can attain good ranking in yahoo by simply having good on site content, meta tags and page titles!

When we work on a site generally it goes onto the first page of Yahoo once we have completed the initial onsite optimisation!