They have pretty much shared above what to do. What I can say is that you regularly build links. Make a few in a day. For instance, you can do a few bookmarking today, and then article submission the next, and then web directories the next day, and so. Mix it up in the next week. You can take a break in a day or two. Just continue doing it on a regular basis. Your backlinks will grow in number before you know it. Be patient! That's the key. Keep Pressing on. Also, be picky with the sites you build your links from. Make those quality sites a priority. Sometimes, the hardest backlinks to create are those from really good sites.