Our job is rough. I have done many things in SEO, and none have even come close to being as mind-numbing and frustrating as link building. It’s been even rougher than usual lately, and that notion is one shared by many of my link-building peers. After doing this for so many years, I can tell you that the summer months can be really, really difficult. Everyone’s on holiday, response rate goes way down, and then if you actually do negotiate a link, you can wait weeks for it to go live (because, again, everyone’s on holiday)!
Unless you’re a magician (or a charlatan), you cannot look at a site and make a concrete determination about how many links are required to obtain the desired rankings and traffic numbers. You can’t look at a target site and accurately gauge how getting a link on it will impact your site. You can look at two comparable sites, one performing well (Site A) and one not so well (Site B), and see that Site A has roughly 5,000 links while Site B has 300. From there, you can recommend that Site B build some more links, because that is obviously an issue. However, that’s kind of where it ends, and that’s what we want everyone to understand.