When creating a link building campaign, one strategy to consider is varying up your anchor text. Let's take the example of "Apples". If you are looking to improve your positioning for this term than you will want to get links on highly relevant sites using the keyword "Apples". But, you will also want to get links that use different keywords like "Red Apples", "Yellow Apples" etc. These different keywords help keep your campaign to be more natural.

It's not an exact science, but if you think about it logically, varying up the anchor text make sense. I mean if you see 100 "Apples" links with no variations than something does not seem right. You would expect the link "Apples" to have some hyperlinked words before or after it.