First of all start letting spiders and users know that you provide a rss feed.
Put the link of the feed into a link rel="alternate" <link rel="alternate" type="application/rss+xml" title="[The title]" href="[absolute feed URL]">
In this way users with browsers like mozilla, firefox and safari will see that you syndicate a feed.
Then add a RSS icon into your pages and promote it on your site.
Don't forget to create a simple page describing some information about RSS and how to use it, with some links to feed aggregators' sites and tutorials. :)
