Root privileges are not required to build a .deb package if the fakeroot package is installed. Install your new package. You do have to be root for this - use su to change to root from an ordinary user. All the debian specific files live in the debian directory. Read with less docfile , or zless docfile.gz for .gz files.
Building Follow the instructions that come with the package.
Many packages have a configure script which will query your system and configure themselves appropriately. Not supported by all software. Some require a file name to build such as make foo . Run as root. Where to look when it doesn't work Read the error messages.