What is a good blog post ?
I would say a blog post is good if it is informative, well-written, specific to the topic. In my opinion, a blog post is different than article, a news story or an essay. Bloggers may not be necessarily a good writer, or a language expert. But he must be knowledgeable on the topic he is writing and express his knowledge clearly in his bog post. For example, a beginner may not write a good blog post on Make Money by Blogging or Search Engine Optimisation, as he is not expert on that!
A good post will have no grammatical mistakes, spelling mistakes and no vague or ambiguous statements. An expert on a subject may not necessarily write a good post on the subject! Even a person who is learning the subject may write a good post about it!

How to write a good blog post ?
Everybody wants to write good post and fill his or her blogs with good posts and expect them to be popular. By popular I mean, read by many people. Number of views or number of comments may not be a good statistics of how many times people read the post, thanks to SEO, Directory Linking, Social Book Marking etc.
To write a good post, try to gather as many information as you can over the topic. Read them, understand them. Then write in your own language the way as you would have explained things to your children.
Put small facts of the topic which are important, but people normally ignore them. This will make your post a special post to read.
Write your own opinion on the topic and let your view be known to people. There may be many article on the same topic, people may already be knowing about it, still they would like to know your opinion on the topic.
End the topic with a closing observation.

Remember, a good post may not be very popular and all popular posts are necessarily good posts.

After few “How to”, I have decided to start “Smart Ways” now. A post is what you have to keep writing on your blog. If you do not write a post, then the blog becomes orphan! Posting for the sake of not making your blog orphan is as useless as it being orphan.

Few points about smart way of writing post:

1. Use MORE TAG
Yes, use MORE tag. This is one of the best part about blogging. You can use more tag and your post will be split. You click on the more tag, whole post will appear in a single page now! Reason to use more tag is to display two or more posts ( along with Post Title) on the non-scroll area of the blog homepage!

2. Use KeyWords in abundance
Use Keywords in your post. Simplest way to put more and more key words in your post is to avoid the words like “it” “this” etc. In stead of these words, use the actual word. The sentences might sound too repetitive, but if you use in your every third line, nobody will notice. But this can do wonders for search engines.

3. Use Reference from other posts
Yes, this helps. If you put few excerpts from other similar and famous posts in a block quote, it not only makes the post look better, but also readers would think the article quite well researched!

These three thumb rules should be enough to write smart posts, bring traffic to your blog through search engines. Remember Search Engine traffics should consist of 70% or more out of your total visitors.