A Few Numbers on My Cold Email Campaign & Questions

I am new to email marketing. With it I sell videos to offline businesses as a side to web design and SEO clients.

Currently I use PHPlist to send emails. I host through HostGator. I use this service because it gives me the ability to import emails, won't penalize me for bounces, email recipients can easily unsubscribe, and I pay one price for 1 subscriber or 1 million subscribers.

Before I used PHPlist I used masked Gmail accounts. This was horrible because I couldn't track anything. And my accounts would be blocked multiple times a day. Annoying.

With Gmail I sent around 400 emails at a time every 6 hours. The only real stats I have are that I was able to get 1-2 new clients per send.

Now I am using PHPlist. Now I can track opens and click-throughs to my sales page.

Here is what I do:
- Scrape industry specific directory websites for emails.
- Import those emails to PHPlist.
- Send industry targeted email promoting my video services. I throttle it so that I only send about 450 emails an hour. This is to not raise any red flags with my server. (as per instructions from HostGator support)

I have hardly started to send (674 emails sent) but I can already see problems.

My stats are:
674 Sent
215 Views = 31.9% Open Rate
44 Clicks = 6.53% Click-Thru to my sales page
8 Bounces
1 Unsubscribe

Problems:
1 Returned Email
0 Calls
0 New Clients

This time my email does not have the pricing breakdown of my videos in the body. In the past I have noticed that most people who are somewhat interested never even clicked through to my sales page. They either call directly or email me with questions.

From this information I believe I need to add pricing back into the body of the email and also make my sales page better.

This may be borderline spamming but out of about 6,500 emails sent I have literally only received 6 people who were not happy with me. With them I have taken them off the list and replied back with an apology. To which 4 replied and were very pleasant in their response.

Do you guys have any ideas or do I really just need to send a lot more out to get a better idea of what I should do?