Running a blog is no easy task and finding time to build links can seem impossible. Luckily, like most things with WordPress, there are plugins to make your life easier. The following plugins are designed to help you more efficiently build both internal and external links throughout your blog.
Let me know if you know of any that I missed and we'll get them worked into the post!
KB Linker and SEO Smart Links
KB Linker has been one of my favorite plugins since I first heard about it from Michael Gray's growing list of WordPress SEO plugins. KB Linker allows you to setup rules so that whenever you mention a specific word in a post it automatically creates a link to wherever you have it setup. In other words, if I was targeting the keyword "red shoes" I could setup a rule that anytime I mention "red shoes" in a post, it automatically sets up a link to the page I'm targeting that keyword on. You can also set a limit to how many links are setup in a single post.
Alternatively you can use the plugin SEO Smart Links which does the same thing.
Broken Link Checker
As your blog gets older and your archives get built out, broken links are almost inevitable. The Broken Link Checker will save you (and your visitors) from the headache of keeping up with broken links and images. With the Broken Link Checker installed, you can be alerted via your dashboard or email of any broken links in posts, pages, to images, in redirects, etc.
This is a great way to ensure you're always maximizing both your user experience and your internal link profile.
Scribe is a great plugin to help you with many aspects of SEO, but also when it comes to link building. Once you've decided on which keyword(s) you plan to target, Scribe can help make sure you've setup the appropriate internal links and will help you find other related sites to the topic your post on. What's even better is that Scribe will find influential Twitter users that you should target to help virally spread your post. Scribe ranges from $17-97/month depending on how many posts you need to evaluate each month.
Yet Another Related Posts Plugin
Another way to maximize your internal link structure is to use a post like Yet Another Related Posts Plugin (YARPP). YARPP will find other posts on your blog that are similar based on title and content. At the end of the post they'll display the related posts with the post name as the anchor text. You can choose the number of related links you want to display.