My best answer is to just start writing. I'm not sure what your blog is about but whatever it is you should be passionate about it. If you were passionate about it all you will have to do is sit down and start writing the first thing that comes to your mind.
Feel free to outline 5 to 7 bullet points so you can have a direction when you start writing. Know what you want to write about and write three paragraphs for each of these bullets.
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