Get some good quality backlinks. The more backlinks you have the better. But be sure to submit it to those updated and trusted sites.
Always go for high ranking page ranked sites, these are always spidered by Yahoo and other search engines, so do this often, hubpage linkbacks do well, but generally just writing great content anyway is a good bet as others will vote for it and submit it to digg, stumble it and allsorts of other thumbs up comments and stuff.
These methods all sound good. However, Yahoo has its own system and I have not meant one person who really knows what it is. I have seen sites take more than a month and I have seen some take as little as a few days. The best advice is to submit directly to Yahoo and just wait it out. The usual ways that people manipulate for Google does not work for Yahoo. In time, your site will be listed and you have a fairer chance to rank well than you do with Google.
Go digg yoru website several times on different pages you have made. (Be sure not to digg your front page).
Right..fastest is via Social bookmarking websites...I have found earlier that so long as my site is not listed in google...yahoo is very excited about it.