The First Step to write a good blog is to select a keyword or a topic so please select the topic that you like the most apart from this you should have good knowledge about that topic. secondly, the content length should be good so please try to make the content of at least 2000 words and use Grammarly google chrome extension as it will automatically detect grammar mistakes in your content.
download WMS everywhere plugin that is a google chrome extension and it will help you to decide your topic apart from this you will get some related topics that are ranking for a keyword with their volume and CPC.
link to download Grammarly plugin.
https://app.grammarly.com/