As with anything you need to make a business plan... easy to forget in the fast paced internet world.
Ask yourself why you want to blog?
- Is it to gain inbound links?
- to build your personal reputation?
- to build your corporate reputation?
- to earn affiliate or advertising revenue?
Depending on your answer you should be able to build some KPI around your goals so that you know if your blog is meeting your criteria and over time you can monitor your success.
The technical side of blogging is incredibly easy - download WordPress (because it's easy to install and use, oh, and free), upload to your server, install and start blogging.
Blogging well takes effort and depending on your goals will take different amounts of effort. There's nothing worse than a website that gets abandoned - and a blog is no different - except that the time stamps tend to be more obvious!