Always acknowledge a comment on your blog and respond to the commentator, preferably at his own blog. Its great to reciprocate the gesture.
After completing your post, read it with a fresh eye from the perspective of a reader to check if you enjoy it or if it needs changes.
Content is the king - In the blogging world so diverse and big, you need to establish yourself with a distinction. the only road to it is good, original and valuable content. Be creative, different and surprise your readers once in a while.