the brute force way: create a folder with DEBIAN/control run:

dpkg-deb --build folder folder

debian/rules is a makefile create a folder with debian/control and debian/rules the rules files create a DEBIAN folder run:

dpkg-buildpackage folder
#or (just to create the binary pkg)
fakeroot debian/rules binary

small tutorial

cd myproject
cd ..
ln -s myproject myproject-1.0
cd myproject-1.0
dh_make -r
cd ..
cp -r myproject-1.0/debian myproject
rm -rf myproject-1.0 myproject-1.0.orig

cd myproject
debuild --no-tgz-check -us -uc -b

this is the top level tools, it create a debian folder with everything you need to call dpkg-buildpackage

dh_make --createorig

debuild --no-tgz-check -us -uc -b