A good habit to improve your blog is to go through your blog as a reader and ask yourself the following questions.
1. What is unique in your blog?
2. Is the information provided relevant to your niche?
3. Are you offering unbiased opinions on topics or just following blogging gurus ?
4. Is your blog essential for your readers?
5. What does a reader lose if he unsubscribes to your blog today?
If you are not providing unique content and personal opinion which is difficult to find anywhere else, you are not a successful blogger. Unless you provide something useful and necessary to your audience, you cannot be called a good blogger.
It is a good practice to go through some of your older posts once in a while. By going through old posts you might find some mistakes which could not be spotted earlier, also you might strike an idea for your new post be referring to older posts. If you through some of your older posts randomly, you might find that there is nothing useful on your blog. There is nothing new that is being offered to your readers and it happens almost 90% of the time.
This is the only way to improve the quality of your blog. Remember a blogger is a reader first and blogger afterwards.