You can promote sponsors on your website via 5 ways:
a) Add a sponsor to appear at the bottom of your site pages with a logo and a link through to their website.
b) Create a widget for your sponsor and place this to appear either in the sidebar or at the bottom of pages.
c) Create a news report about your sponsor. You can let this news item appear within your standard news and in addition you can link into this page via content created in options (a) or (b) above.
d) Add a sponsor logo / header and add text to your header
e) Add your sponsor to the "About" section of your site