I dont use sites such as Digg or StumbleUpon but is it worth spending the time promote them on here?
Yes. When promoting a blog, I'll typically use linkedin, facebook, twitter as well as digg, delicious and StumbleUpon. If you use B2B, then linkedin is going to be your best bet (as already mentioned).
Your blog must have unique and quality content and it should be intresting and informative.
I would suggest you to write user-friendly content. Because people loves to content that is friendly manner. I hope that would get rank over search engine website.
First your blog post should be unique, post interesting information and make SEO to your for promoting. If you follow these steps you definitely attain good result in blog post writing.
I hate it when people say things like this. I think it goes without saying you're not using duplicate content for your blog. You're probably writing very nice articles, but nobody's viewing them and you're wondering what the heck the point is. Without seeing examples of your work I can't really tell what (if anything) you're doing wrong.
Are you targeting your blogs? Are you asking yourself "who am I aiming for with this blog? Who is going to be my audience?" Chances are, you're just writing the blog. Next time, try and thing about who you're going to target before you put pen to paper. Another good method is to play "Devil's Advocate". Think about the top issues in your business at the moment and try to offer a fresh perspective. It doesn't matter if you agree with what you're saying, you're offering a new perspective on a hot topic.