Build Debian package from source

Prepare build environment:
$ apt-get install debhelper graphviz pkg-config

Download source package:
$ apt-get source packagename
Downloads: a .orig.tar.gz, a .dsc and a .diff.gz.

Auto-build package:
$ apt-get -b source packagename

Build later:
$ cd package_directory
$ dpkg-buildpackage -rfakeroot -uc -b

Install package:
# dpkg -i file.deb

Source: Apt manual