Tangier in two days
A relaxed plan: the old city on day one, the coast on day two.
Day one belongs to the old city. Walk the medina, visit the Kasbah Museum and the American Legation, and stop in the Mendoubia Gardens beside the Grand Socco.
Day two is for the coast. Drive to Cap Spartel in the morning, see the Hercules Caves, have lunch by the ocean and return through Perdicaris Park.
Keep both evenings free for the Corniche and the marina, when the whole city comes out to walk.