The best thing you can do to improve your search engine placement is to get incoming links from respected external websites. But it's also helpful to embed links to your products and services within your own blog articles. The anchor text (the text the user clicks on) of these links is extremely important. It should contain the keywords that users are likely to search on when looking for the product or service promoted on the page being linked to. Here is an example from the bottom of Webucator's recent blog article on Google Analytics highlighting this tip:
The "Google Analytics training" link code looks like this:
And the results of this kind of work? See below:
It is much better to get incoming links on external sites, so your bloggers should keep this in mind if they ever do guest blogging.