you only need few backlinks from high pr sites and regularly this is to prevent search engines from detecting spam
Just go for 10 top bookmarking website for 1 URL which will help you to gain good ranking in SERP for targeted keywords.
Try finding quality social bookmarking sites so that you won't have much time for creating submission with useless or low quality social bookmarking sites. Use other methods of link building too, this way you can create as many quality links as you can....
@ stephenj141 i have bookmarked my URL in almost 10 different sites . What about Twitter, Facebook and Google Plus which are also including as a Bookmarking site?
@webdev007 thanks for your advice. I did 10 PR sites including Twitter , Facebook and other social media
Just share my personal methods, when I post a new article, share it to social media, wait for a day, and than share to 20 social bookmarking site. No reason your site will detect as spam, since the function of social bookmarking site is share the web contents good luck
You could do a keyword analysis relative to your competitors, of what you need and then use Synnd to get the quantity required. This reduces guess work and helps develop a business mindset. I have a Fiverr gig for the analysis so PM me if you need help with it.
I use to do 40-50 social bookmarking per month for my single url and try to get published links from bookmarking sites.