We all know how past SEO worked - There were countless ways to create hundreds of links to your website, (including a myriad of black hat, quick link techniques) and your site will rank.
Gradually over time, Google has caught up with all the dodgy link building techniques out there, and will penalize sites that use them.
Put simply, it is all about quality over quantity now.
Today's SEO is completely related to content. You need great content before you start any link building. And rather than calling it link building, you need to think about content marketing, i.e getting your content out there for others to link back to it.
Ranking a site in today's online world requires patience and as I say, an investment in time/money into the content you place on your site.
And if you do want to pay for your links, you have to very careful. One of the most reliable methods available now, is a very secure private blog network of quality domains. This post will be too long if I go into that here. However, anyone interested can email me at [email protected]