A method for manufacturing a tower structure of a wind turbine at a wind turbine site. The method includes determining an optimized shape of the tower structure based on one or more site parameters. Further, the optimized shape of the tower structure is non-symmetrical. In a further step, the method include printing, via an additive printing device, the optimized shape of the tower structure of the wind turbine at the wind turbine site, at least in part, of a cementitious material. In addition, the method includes allowing the cementitious material to cure so as to form the tower structure of the wind turbine.