It rarely does. Baneful magick is not the same thing as a bullet to the head. It will take as long as it takes.
If at all possible find a secluded place outdoors for your baneful work. Not only will it give you privacy, but, if you will not be saturating your living space with baneful energies that will affect you just as much as the target.
Try the chant to call legions of black angels. All you have to do is chant until you feel a presence and then give your command (the presence will be behind you)
You can also chant the demonic enns from EA’s book Baneful Magick until you feel presence and give them a command: