Post Ideas: At times you will just run out of ideas for post not sure what to do. use google and apps like Evernote to note down all that ticks in your mind. Something will surely turn into a new post.
Tags: Use of relevant tags is important from the SEO perspective. It helps the search engine track your post based on the tags you use.
Grammar - Depending on the language you use, blogging just makes it imperative that you are reasonably good with your grammar skills and proficiency if not a master. Remember your audience is a mix of both; the ones who are experts and the ones who are not.