The ability to point your toes while at the same time keeping the ankles relaxed comes with greater flexibility in your ankles. You can try a variety of stretching exercises to develop ankle flexibility - although take care to not push yourself too far. Ankle flexibility also comes with practicing your kick consistently. When you point your toes, only point them as far as you can without stiffening up your feet/ankles. Even if you're not pointing your toes perfectly, you are still on your way to a proper kick.