Links that are tightly related to a keyword combination have a much stronger effect on its specific ranking. Their effect regretfully isn't very broad and your site needs links in various degrees of relevance.
So where do you start and how do you build a link profile to stand the test of time?
For most websites it is best to start out with links in a broader theme. This allows you to rank for all keyword combinations present in the content of the site as long as the competition is slightly milder.
Broader link building can make you grow to the next league, opposed to specific links which only effect a few keywords. Once ranking indicates that you're getting close with your broader approach, you can start focussing on more specific links for that last specific boost.
Baseline Measurement for Attainability
Start out by tracking your ranking across a large number of relevant themes.
Track keywords in various levels of competition and make sure you put in the same textual (and technical) SEO effort for all of them. This way ranking is mainly based on your links and how these compare to the competition.
Your current level of competitiveness becomes clear when keywords rank close to the top-10. This baseline provides a great indication on where to focus your future link building effort.
Broad Link Building
Is there a theme you can deduct from a large group of keywords just outside your top 20 rankings? These themes are the best targets for your next link building efforts. Step-by-step they form the basis for future themes which are currently beyond your grasp.
Good link partners are the websites that rank somewhere within the top 100 for many of the keywords within your chosen theme. Select the ones that might directly link to you first and add the remaining important ones to a list for further investigation.
Investigate these top 100 websites for their link partners and the websites they link to themselves. Hopefully this provides a large list of link prospects. If not, you can always try to broaden the keywords and you can even go for partial keywords to find relevant link partners.
The links you acquire should have a mix of landing pages, anchor texts, and other relevance factors. The resulting link profile should communicate to Google how broad your website is viewed by others.
Your ranking should shift across the board. Various top 30 keywords should become top 20, top 20 should become top 10, and if you're lucky some keywords will even climb within the top 10.
More Specific Links
Once you're getting close to your desired top positions it might be wise to investigate how close you are for each keyword. What are the websites above you doing that your website isn’t and can you match that?
Try to use keyword ROI to see if you should be willing to put in the additional effort for that single keyword combination. Combine multiple keyword combinations into a single link building activity to make it more lucrative. Because you’ve build a broad link profile as the basis for your ranking, the effect of each additional link will also be broader across more keywords.
Links for specific keywords preferably come from websites ranking for that keyword combination. You can always broaden the search grid for potential link partners slightly, but remain focused on exact anchor texts with this last link boost.
Where broad link building allows a lot of textual freedom to even incorporate accidental keywords, specific link building should focus on a single keyword combination.
From Broad to Specific
The graph below shows how various keyword within a theme are effected by a broad link building approach:
The following graph shows how this differs when you focus on specific links:
This last graph shows how you can first focus your link building effort on a broad range of keywords and how underperforming important keywords require a much smaller additional boost from that situation.
Link Building is Logical
Everything in this article should sound perfectly logical, but regretfully very few link building activities are set up this way. Most of them focus on that one golden keyword without any regard for a much broader view. Benefit from this insight while the competition isn’t.