The first step in creating a genealogy blog is choosing a platform. There are many choices for blogging these days. This article will discuss only a few and go over some of the basic differences between them, but there are many you can choose from, so look around before you make your choice. The best way to do this is to Google blogging options. The first two pages will probably give you the best options.
Blogger is one of the most extensive blogging platforms. It is versatile and has a lot of users already. A large number of genealogists already use it, so you would be able to connect easily to their blogs. Blogger uses widgets that can easily enhance your blog with visitor counts, twitter platforms, and many other things that can give readers information they might like to know about your blog or subject. It also has the advantage that Blogger is part of the Google community, so if you already have GMail or a Google Plus account, there will be less for you to do to sign up.
Wordpress is the other large-scale blogging platform. Many genealogists have Wordpress blogs, and it makes up a good percentage of the genealogy community. It is generally similar to Blogger, though it has a great deal more customization options available. One downside is that the blogs themselves are stand-alone, and less connected to other Wordpress blogs, which makes it harder to connect to the genealogical community without extra widgets on your blog.
Another possibility is Livejournal or its clones. Livejournal is becoming less fashionable now, though, and the genealogy community has a smaller presence there. These are the simplest to jump into quickly, but are less easy to connect to the genealogical community. The Livejournal clones have similar styles and limitations, though each has its own variation of the Livejournal code, and Livejournal remains the most popular of all of them. For a list of Livejournal clones, see this list.
Most recently Tumblr has become a sort of replacement for Livejournal, though it is more graphics-based than Livejournal, and again is less connected to the genealogy community as a whole. One upside is that it is very simple to create new sub-blogs so you can divide your interests better. You could even conceivably make one blog for each of your family lines.
Other sites of note include Twitter and Pinterest, though neither is specifically a blogging platform. However, as many genealogists use one or both, they are worth getting accounts with so that you can follow your fellow genealogists there as well. There is also Facebook, of course, which is good for keeping in touch with family and asking questions, though not as good for blogging. It can be used to get in touch with extended family in hopes of finding distant cousins also doing genealogical research, though, and so should remain a part of your social media for that purpose alone.
Each site offers its own benefits and problems, but all are valid choices. If you're simply going for a place to put your thoughts and questions, Livejournal or Tumblr might be best. If you want a more in-depth, professional looking blog, Blogger or Wordpress are the better choices, as they will connect you to many other genealogists using them. Whichever you choose, take time to research the site, and make sure to set it up properly first before beginning to use it. The next article will go into a few details on what to include in a basic genealogy blog.