Making a LEGO minifigure run is a very tricky. Balancing the minifigure is what makes it so tricky. Some pointers for when you are working on your run cycle is watch the minifigures back. Try to keep the back slightly leaned forward and at about the same angle at all times. Also say the left leg is forward the left arm should be back and the right arm should be forward. The picture below will show what each frame should look like.