How to get the build procedure for a Debian package?

I want to build a version of some software that is more recent than the one that is currently available as a stable release Debian package. To do this, however, other than using a more recent version of the source code, I would like to follow, as closely as possible, the build procedure that was used to build the Debian package for this software in the stable release. At the very least, I would like to specify the same configuration flags and the same values for relevant environment variables during the build as was done for the stable release Debian package for this software. **Q:** How can I find the build procedure for a specific (stable release) Debian package?