If you have set up your blog in wordpress there might be possible that you might not have used some of the functionality of wordpress related to its appearance, look and theme. Below are some of the functionally you may test and perform in your wordpress blog.
Simplifying category and tag into one page : Some time the Value of the blog get distributed on the pages which are not much important for promotion of blog and which are for users to categorize data more accurately. Different page URL of tags and category pages are ideal example of this. You can specify the same page to consider for creation with this option so same post doesn’t get repeated for different category and tag pages.
Changing the URL structure of the page : Instead of having URL structure which include date, month and title, you can create custom URL which includes your title or month only. You can choose couple of option about formatting the URL the way you want by default it would adopt the structure with date and month. You would get this option at writing option from Setting.
Changing the placement of the content and enabling or disabling certain section. In ideal blog, post is being displayed on left, categories and tags are on right and menu at top. You can change the placement of each one and see which one looks best. You can also enable certain changes and see which theme your visitors like most. You need to go to Setting -> Theme option to execute these things.
Adding and Deleting widgets: Default WordPress blog have category, tags, author, comment and top commentator widget on left side of the blog which would stay common in all post. You can add and edit new widgets like displaying RSS feed from your favorite site or integrating news module from setting menu.