I have written a number of applications and libraries (some of which depend on third party libraies), on my home workstation (Ubuntu 9.10).
I now want to create packages (one package per application/library), so that I may then install them on my server, which will be running Debian OS.
Any guidelines/gotchas on how to go about creating installation packages for debian on Ubuntu?
First, be aware that although Ubuntu and Debian use the same packaging system, a package built for one might not work properly on the other due to differences in installed shared libraries. If you're packaging compiled code, you might want to keep a Debian virtual machine around (perhaps using VirtualBox) to rebuild your package for Debian once you're satisfied with it on your Ubuntu workstation.
That being said, there is a wealth of documentation available on deb packaging. Keep in mind while reading it that it's mostly aimed at people who are packaging someone else's code. Since you're both the developer and the packager, you have the luxury of creating Debian native packages, which basically means that you'll be including a "debian" directory in your source code instead of creating its contents with patches.