Having a good ranking will mean better traffic (depending on the demand on the keyword you're looking at). Having alot of traffic will not necessarily mean better ranking, but in some cases it does have an effect (pull marketing). If a topic's hot and you're the only one with the content you're gonna rank, whether the page is brand spanking new or not.
I would suggest you do some more reading on
SEO before you go
SEO'ing your website. Remember it's not a magic bullet and it's a long term strategy...