I use mk-build-deps from the devscripts package for this (you’ll also need equivs).
mk-build-deps
will build a package depending on all the build-dependencies in the debian/control control file; that package can then be installed using apt, which will also install all the missing dependencies.
The advantage of this approach is that uninstalling the dependency package, once you’ve finished with it, will also identify any build-dependencies which could also be uninstalled.
To reduce manual steps, the following command can be used:
mk-build-deps --install --root-cmd sudo --remove
The end result of this is that all the build dependencies are installed, but not the newly-generated build-dependency package itself: it’s installed (--install), along with all its dependencies, and then removed (--remove), but the dependencies are left in place.