Beyond the release announcement for Debian itself, you will want to put some thought and work into a release announcement for your subproject. This will not only be directed at the Debian developer community but also to the users. This will include potential new Debian users abroad, who may not be on a Debian mailing list, so put some thought into which non-Debian lists are appropriate for posting your announcement.
I expect by this time people have newly installed Debian along with your work, or have installed your subproject's packages on their existing Debian systems. Now comes the fun part, building relationships with your user community.
Users are mixed blessing. While you were still just developing, you might have had some developers as users and some intrepid "early adopters", but once you have released, your first version is "out there" and you're necessarily going to attract all kinds of users who are not necessarily as technically savvy as your small development user community. Be prepared to spend some time with them. Be patient with them. And be listening carefully for the underlying questions beneath the surface questions. As draining as it can be to deal with users, they are a very key component to keeping your development effort vital.
Should a user list be created? It's not as cut-and-dried as it might at first appear. When user help requests start coming in, you might at first see them as a distraction from the development effort. However, you don't necessarily want to "ghettoize" the user community into a separate list early. I think that's a recipe for developers to get out of touch very quickly with the users. Tolerate the new user questions on the developer list for a while. Once a user list is finally set up, courteously redirect user questions to the user list. Treat your users as the valuable resource about how your project is working "in the field" that they are.
Fortunately, we're not in the business of supporting users alone. Look beyond Debian for your allies in user support: Linux user groups (LUGs), the users themselves. Develop an awareness of who has stakes in seeing your project succeed, and enlist their help in getting a strong network of support established for your work.
Debian Subproject HOWTO
12 February 2003synrg@debian.org