 Vertical fists, like this, keep going, this space. Fist over fist, do not punch in two different spots, punch just one spot in front of you, at the chest level, like this, one, two, at this speed. Don't rotate your body, keep your shoulders square, keep your hands relaxed, keep your fists half closed at this point, keep your shoulders relaxed. When you pull back the fist, pull back the fist under the hand that goes out. Your fist should go back to about two inches from your chest.