By the end of 2004 blogs had established themselves as a key part of online culture. "Blog readership shoots up 58% in 2004 6 million Americans get news and information fed to them through RSS aggregators But 62% of online Americans do not know what a blog is." - Pew Internet & American Life Project

Tip #1 - How and Where Should I Start?
You should begin your blog with a free blog hosting service
such as Blogger (http://www.blogger.com), or other similar
free services such as JournalHome.com, LiveJournal.com or
Blog-City.com. The learning curve for using such free
services allow you to spend more on developing your content
rather than worrying about the advanced areas of scripting,
hosting, or programming.
Tip #2 - The Things You Should Decide to Write About
Although not a required prerequisite for you in order to
write a blog, it is highly recommended to try to find a
topic to write about based on your level of interest and
knowledge. The higher your level of interest, the easier it
is for you to get your quality content posted on your blog.
Always try to choose an area which you can enthusiastically
write about on a daily basis.Try to pay attention to a niche
which suites you well. A niche is basically a targeted
product, service, or topic.
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24 Tips and Strategies on How Everyone Can Blog Right and Get Everybody to Read