I think a good blog should have all of these in it.
A title, you are supposed to write a title because that tells the reader what you are writing about.
Paragraphs you have Paragraphs to space out your writing.
Your writing should be punctuated so your reader can make sense of it.
Your writing should be friendly and informal because it is available to everyone.
The blog should be written in first person like using I or me. This is so we can connect with the reader.