Hey Luke
As a general rule of thumb, blogs will offer up a fair bit of duplication through tags, categories and archives so it can be worth not indexing those pages. For the posts themselves, you should have the option to create a unique snippet rather than using the first couple of blog paragraphs if you wanted to do that (best practice) but the duplication of the blog posts should be handled by the canonical tag so there is only one true instance of the article on the site.
You don't mention which blog package you are using but for WordPress, the yoast SEO plugin will help you easily deal with most common issues.
http://yoast.com/wordpress/seo/
The plugin does not do this all on installation and requires some simple configuration to fit your circumstances but the following page walks you through the configuration of the plugin so you can make a call on what to index, noindex, etc.
http://yoast.com/articles/wordpress-seo/
What if you are not using WordPress? Well, I would still read the above article. It deals with issues common to most blog platforms and covers technical optimisation, template tweaks, site structure, conversions and most importantly for you (section 3 I think) covers duplication created by the blog, pagination etc.
Well worth a read if only to get you thinking in the right direction and if you are using WordPress, then the plugin and that tutorial will put most of your problems, if not all to bed.
Hope it helps!
Marcus
