Hi! Great question! My name is Humberto Valle, I'm a global competitive strategist and run a hybrid agency out Texas. A lot of our own clients come to us with existing notions about how SEO didn't do anything for them, etc. only to find out that they were previously sold link farming and junk that is obviously all just fluff and ego boosting but creates no real investment.
Good PR backlinks are a management level effort, we for example develop an overall strategy for the use of the links, where these links will point to, what will be offered on these landings, etc. we then craft content and write it and find channels that can get us to prospects' eyes.
If you try to hire someone off craigslist for example, you will have a difficult time trying to get them to provide you with samples of previous work, if you go to a typical marketing agency they will charge you thousands of dollars for this services. Good PR links are hard to build and require getting other people involved such as bloggers, influencers, high traffic online mags, etc. If you are interested, feel free to contact me and let's see if we can be of help - for us our SEO and back linking is dependent on the service or product.