Many bloggers must have made use of the free Disclosure Policy Creator from http://www.disclosurepolicy.org/ which helps you create a Disclosure Policy whether or not you get paid to write certain content on the site.
Respecting User Privacy
If your blog / website uses and stores cookies on users PC, disclose this up front.
Tracking / Statistical Data Collection
If your blog / website uses tracking or statistical websites like Google Analytics or any other such websites to track users, make a small note on what information is collected by which tracking software and disclose that you will not share the information.
Make a note on how users can comment on your site along with making it clear that comments approval are at your sole discretion.
Credit Card Acceptance or Not
Tell the user up-front whether or not you accept credit card details from the user as part of providing a service to them.
If you link to external sites make it clear that you are not to be held responsible for the external content.