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.
People come to your blog out of choice and not any compulsion. If you remember this, the rest is not important enough.
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.