I have a hub on this topic so you wish to head over to my profile and read it. In brief to answer you question:
(1) Create and publish good quality hubs
(2) Use Social bookmarking (i'd recommend you use OnlyWire) it allows you to backlink your hubs to more than 30 Social network sites in one go. By the there is a FREE version you can use again covered in my hub.
(3) Read other peoples hubs and leave insightful comments - 7 out 10 people will reciprocate and do the same for you.
(4) Ask and Answer Questions - people my visit your hubs
(5) Read other blogs and leave comments specific to the Hub you wish to backlink - leave behind your hub URL when asked for website details when you comment on other blogs.
Hope this helps