need suggestions on WP-SEO

I have converted one of my HTML sites to WP and it seams that i have dropped some ranks in google after the change. So i was wondering what suggestions could be presented to apply some META back into the posts. Playing around with SEO ultimate plugin which seams handy but i am still testing what works best.

also wondering if link structure has a huge difference, i have mine set to works not numbers figured it may help.

But any advice would be great while trying to learn how to apply some goodies to WP.

cheers