You may want to keep in mind the following rules:
If you think a post will take more then 6-7 minutes to read, you may want to consider dividing your post into several shorter ones.
Remember, visitors will read your post on screens, and not on paper, and surfers rarely stay longer in front of one page.
The button "Read More" on the bottom of the post editor will insert a divider splitting your post into "preview text" and "main body" text. When visitors view your blog page, they will only see the preview text, and this will allow them to easily browse threw your blog posts, and will make your blog more presentable and appealing.
Don't use too many bold text, but do use them when you want to emphasize things, use list tablets when needed, etc.
Remember, if your blog is not appealing to the eye, it is less likely visitors will stick around and read it, regardless of how amazing you posts content is.