The Third Commandment of Blogging

Thy Blog Shall Be Readable

Learn to spell. Learn to construct sentences. Learn to construct texts. Use whitespace and blank lines responsibly. If you blog in English, use this; if you blog in another language, read your local equivalent.
Remember that the primary goal of language is to communicate. Stick to the point –and make sure you have one. Avoid rambling, going off on a tangent, repetitiveness or anything else that would make your conversation partners roll their eyes in real life.
Write invitingly. Draw the reader in with the first sentence of your posting and keep them hooked.