The first and foremost step while building a blog is choosing the best CMS or platform for your blog. There are many blogging platforms at this era of developing blogosphere. Some of the best blogging platforms are wordpress, blogger, live journal, joomla, nucleus, PMachine, Greymatter, B2Evolution, TextPattern etc. There are a few pros and cons for each of the platform which normally leaves the new blogger into a confused land who finds it very much difficult to find the best CMS for blogging.
I have tried each of the above and a few other blogging platforms and also read in many other places, that wordpress is the best and satisfactory platform used by bloggers. Most of the large bloggers in the blogosphere have been blogging at wordpress.
Now coming to things like hosting and domain, blogs can be self-hosted or free- hosted.