CMake/CPack is great for quickly packaging for Debian.
However for instance, you may want to package a daemon and let the debhelpers help you with update-rc.d-calls in your postinst/postrm-scripts or other stuff. CPack doesn't let you do that out of the box.
CMakeDebHelper to the rescue!
The modules in cmake/ can be used for that exactly, check out the whole repository to see a working example.
Please use out-of-source builds, in-source builds are a bad thing.
mkdir build && cd build && cmake .. && make package
More information can be found on my blog-post: http://knzl.de/cmake-debhelper/
Debian Packaging reference: http://www.debian.org/doc/manuals/maint-guide/
CMakeDebHelper: Copyright (C) 2013 Sebastian Kienzl; Licensed under the GPL v2, see LICENSE