Models in 3.0.6

If the model is named "Blog_model.php", then load it like this:
$this->load->model('blog_model');
So include the _model part, not just "blog".
And when you call a method that's part of the model, type this:
$this->blog_model->method_name();

Thank you Wouter60 and everyone else for your help.

I knew it was me - I just couldn't see the trees from the woods.