It is just a computer program which takes care of a massive amount of data. For that reason, Google is not perfect and might actually have more imperfections than are visible to us end-users.
But there are some things Google is quite good at. For example, if you blatantly use the wrong techniques to game the system, you will almost certainly be caught and dealt with.
Search engines are designed to reward natural link building behavior and penalize attempts which focus on gaming the system. If this were not the case, Google`s users would not experience the high quality of results they experience today.
So, in order to get into the good graces of Google (and all other search engines), it is very crucial to have a backlink profile which looks natural. Although every seasoned internet marketer knows this fact, creating a natural-looking profile is a little difficult to do. Out of the many new websites that I have browsed,  the vast majority of  websites have highly un-natural backlink profiles.
For example, when I check new websites using the Backlink Watch Tool, most of them show links using the exact same anchor texts. At times, 90% of the links use the same anchor texts and most of the links are pointing to the homepage!
This looks highly suspicious, attracts a lot of attention by Google team, and might result in penalties or even de-indexation.

In my opinion, it is better to build links for the homepage as well as all the inner-pages of the websites. In doing so, care should be taken to not rely on just the main keyword, but also to use many other keywords in there.
In a natural backlinking profile, the anchored keywords would include “here” or “click here”, because if others naturally link to your website, they do not care about your anchor texts at all. So in order to mimic the same effect, make sure you have these “irrelevant” keywords in your anchor texts. Although doing so does not really help you from a keyword-targeting perspective, it will help make your website less susceptible to penalties.
Remember, it is always better to focus on multiple keywords in your backlinking campaign. Just do not go overboard with it. For example, if you are putting up 100 links, do not select 30 keywords. Instead, for each link building campaign, try to focus on 2-3 phrases for each page.
Another important point would be to good links from many different locations. Do not just submit to 1000 directories and expect to rank number 1 for your term. You might actually be backlisted in the process. As far as link building is concerned, diversity and multiple sources is the key!
Here are some ways to get links in order to make a natural looking profile:
1. Submit to high-end directories (and not the free ones). A few ones are, DMOZ and Yahoo! Directory
2. Write articles, spin them and submit them to top quality article directories such as GoArticles, Ezinearticles etc. You can even submit to hundreds of article directories. Just make sure you provide quality content.
3. Participate on forums such as Warrior Forum.
4. Ask and answer questions at Yahoo! Answers. Help others, and where you feel it to be n0n-spammy, link back to websites or webpages.
5. Send a press release out once in a while. Not the free ones. Go for the paid ones at PRWeb.