When it comes to outsourcing search engine optimization (SEO) efforts, Search Engine Land editor Danny Sullivan says the best plan is often to go with a hybrid strategy: work with an external SEO agency to stay up-to-date on SEO news and new techniques while integrating your own routine, in-house practices. When it comes to picking an SEO agency, Sullivan says the most important thing to do is reach out to references to verify -- as with any partner you work with -- that they're up for getting the job done right.