To increase Google ranking you need to make good quality backlink. One good quality backlink can increase your PR.
I'm new to this forum .. But in SEO or rankings in google is my job.. Base on my own studies always do link building on organic way from that google will notice that you are a person not a bot. Organic link building is the best way to have a good rankings in google.
I agree with dailytrans, but I also gotta say that there are a lot of marketers out there who build tons of backlinks at once and big G still likes them for it. I think you just need a variety of different links, for example have profile links, social bookmarks, Web 2.0, etc. That makes it look more natural. But Google can't just sandbox any site that gets tons of links at once. That's how viral websites get started, and Google doesn't want to kill the next Drudge Report, Facebook, icanhascheezburger, etc.