So you're trying to build a Debian package from an upstream source tree, but you're not sure what build dependencies you should install?
I have this problem all the time. For example, if I wanted to build the unity source tree into a debian package, I'd branch it:
$ bzr branch lp:unity
...change into the directory:
$ cd unity
...and then try and build it. Needless to say, I almost never have the required build dependencies installed. You can try and use apt-get to install the build dependencies for you:
$ sudo apt-get build-dep unity
But that reads the build dependencies from whatever version is present in the distribution, not the dependencies in the source tree.
The solution is easy. First, install a couple of packages:
$ sudo apt-get install devscripts equivs
Then run this from within the source tree to install the build dependencies:
$ sudo mk-build-deps -i
If, after this command completes you still cannot build the package, you should probably file a bug against the upstream project!