This is still a debate. Google has a loop hole where some poor quality blogs are still in High SERP, although the contents are so poooorr and a lot of aggressive spammy backlinks pointing to them.
That depends on the type of backlinks you're doing. If you're utilizing different methods (Videos, Articles, Wikis, Blogs, Adverts, etc.) you can do a bit more, but you can't really put all your eggs in one basket in one day. If you do any sort of article marketing at all, Matthew Woodward has a really amazing tiered link building guide here: http://www.matthewwoodward.co.uk/tutorials/the-ultimate-guide-to-tiered-link-building-part-1/ It's super comprehensive and actually a few hours long. I use it myself and it is awesome. I'm using it to jumpstart a fiverr gig right now. He advertises some really cool programs, and I strongly recommend you get them if you can afford them. But if you can't, there are free alternatives available... you just have to find them.
One should not focus on quantity but one should focus on quality. Do 20-30 back-linking every day but write quality comments and do not just spam. Few back-links from top quality sites are better than large number of back-links from poor quality sites.
Hello @Aqib Shahzad, Quality Backlinks never mean more and more links. Better includes some of the ingriedents like; Relevancy of the topic Accuracy of the Topic discussed Right answered or comment on topic No spamm-- Here and there's thing in words. Niche based link creation from the same industry. Thanks @Aqib Shahzad I hope i have defined the as much i know