The average person who reads blogs is doing so because they do not want to read pages and pages of text to get the nuts and bolts of post.
Anymore than four sentences in a paragraph is going to lose the reader by being too meaty.
One way to keep the reader interested is by using lists to when writing blogs.

• The "Top 5" or any number is a great way to use a list.
  Is your blog about poker? Then write about the top five casinos in Las Vegas.
  Write short paragraphs about why their pokers room ranks in the top 5.
  
• Writing about the "Best 10" is also another method that is effective at getting the readers attention and keeping it.
  They are going to read everyone to see what the last one of the list is.
  
• Everybody wants to learn new and easier ways to do tasks.
  This is one of the most popular of all the list types because it gives the reader new ideas and spins on old topics.
  This can be the difference between a redundant blog and one that is kept fresh.
  
• Do not forget to use a list of tips such as "4 Tips" on the topic that the blog is going to cover.
  Readers really enjoy reading tips that can make their lives easier and can allow them ways to free up more time.
  

Lists are a great way to capture the reader's attention.
Keep the paragraphs brief and do not use too many words to convey the point.
This is also going to keep them reading.