The number 1 requirement for ranking well in Google today is AUTHORITY. Without it, you won't rank for much of anything! Authority is absolutely critical to gain Google's trust and convince Google to send you loads of free, organic traffic!
Submit news, post your contents, create your profiles, and drop your site's URL without any reciprocal link from your site. Once you create these high page rank backlinks, they will be a source of web traffic to your site for years to come.