If you want to have a high quality blog, there are some things that you should avoid. One of those things is focusing too much on the form and not the content. There are many ways you can improve the quality of your blog by making it look more professional, such as using some advanced html programming or other tricks. However, ultimately the content of your blog is what is really important. I cannot emphasize this enough, content is what brings visitors to your site, and this is what you should focus on.
Another thing that you should avoid is stealing content. By this I mean a person copy/pasting posts from other blogs and not giving credit to the author. Sooner or later people are going to notice such behavior and will prefer to read such posts from the website of the original author. On the other hand, if you get an idea to post about something by reading a post on another blog, and write about the same topic on your blog, it does not mean you are stealing content. As a matter of fact, I sometimes get ideas what to write about on my website after visiting other blogs.