Leaving shallow comments in response to posts damages your reputation. When you comment on a post, try to put more thought into it.
Add something to the discussion, or put specific reasons why you think it's a nice post.

Here are some guidelines: https://steemit.com/steemit/@miti/newcomers-minnows-and-spammers-this-post-will-save-your-reputation

You may be surprised at how quickly you can improve your reputation!