The problem here is that you have created new sites which on day one have zero authority, zero traffic and do not rank on the serps. Backlinks from such sites are weak.... It will take time for you to grow your tier 1 sites which done correctly over time will provide beneficial link juice... One approach to strengthening your tier 1 sites is to create tier 2 sites which provide backlinks to tier 1 overtime as well as sending other signals e.g. social shares, bookmarks etc... and again rinsed and repeated with tier 2 and perhaps tier 3 level.
With that said done wrong with G detecting unnatural link building and you'll find such links will be discounted or worse could contribute to a penalty e.g. penguin....
The best links you can get are from well established sites which are ranking, have traffic and possess a level of authority/trust - ideally on the home page.... My recommended approach with getting such links is either through guest posting or that you develop a PBN with purchasing old domains which have great metrics plus with resurrected content and valuable backlinks which for sure provide much more link juice than what you are doing currently...
Hope that helps!