...I feel the blog didn't really succeed, and I don't know why.
Gaz, don't change what you're doing if it's really what you want to do. If the blog wasn't successfully interesting and thought provoking, we'd have let you know. Since I'm only assuming that what you meant by 'succeed' was to reach a somewhat wider audience, please ignore the following if that assumption is wrong. I have experience dealing with people who consult to bloggers/podcasters to make them successful, and I can share the basics (in order of importance):
1. Create your content based on something you have a real passion for, because only that passion will make you want to keep doing it on a regular basis indefinitely. It is
always fatal to be imitative.
2. Do it on a regular basis, and be as regular as possible. This is critical for audience retention.
3. To proactively expand your audience, spend at least as much time on other people's blogs making comments (2x -3x is recommended) and aggressively use features such as trackback. Whenever the comments mechanism gives you the chance to include a URL with your comment, do so. It is perfectly acceptable to mention your own blog in your comments, as long as you are polite about it. If you make a good enough impression on other bloggers they will put a permanent link to you on their page (and you probably want to look for other bloggers who have already linked others on their page). Note that there is an unwritten rule of quid pro quo on this, and you can take the first step if you are inclined.
4. Repurpose your content in any and every way you can think of. There are literally millions of websites that are desperate for any kind of remotely useful content.