A few thoughts come to mind as I'm reading through this. First of all, you are definitely working hard and focusing on the right things. It's all about activity, when the numbers are there the placements will follow. That said your 1 to 8 ratio is a little high. Mine and a few of my colleagues tend to see more in the 1 to 4 or 1 to 5 ratio, so for every 4 or 5 sendouts (interviews) we can usually count on a fill. So, you may want to look more closely at why your number is that high, are you not screening tightly enough?
How well do you use your database? Do you put all of your data in there and go there first for all new searches? I've always been amazed at how many recruiters don't. They first jump on the internet or the boards or post the job somewhere before digging into their own data to find the gold already there. The first thing we do is search our database of current and past candidates and then shoot an email out with job description and comment to call with questions or forward along to anyone they may know. This is by far our best tool in getting great candidates, especially because in many cases it shakes loose referrals of people who are not looking and not out there on any boards.
As a one man shop, another thing to seriously consider if you are not already doing so is to partner with a few other recruiters that you know and trust to do splits. This gives you vast leverage fast. It’s how I work. As an example, I share an office with a fellow recruiter, a good friend. We each have our own separate companies. We also work virtually with other former colleagues who are now on their own either in offices or working from home. So, whenever any of us gets a new search we email it out to the group of 5 or 6 recruiters and everyone checks to see who they have and depending on their interest and time, will either dive in and recruit or at least shoot an email out after doing a search in their database. To give you an idea of how effective and lucrative this can be, I just sent a new search out two days ago to the group, they sent their emails out through their databases and I’ve received some great candidates. In addition, from her email that she sent to 2000 marketing people in her database, my colleague not only got a superb passive candidate, she also heard back from a hiring manager who needed a marketing contractor and we got three people set up yesterday and they hired one today. So, one job filled and another strong possibility for another soon.