*feet should be even balance on both sides of the centerline unless you are doing something like attacking or evading.
*when you move you should end up in the same position (concerning balance and comfort) as when you started. the exception is when you are positioning yourself for something that requires a different kind of position.
*when moving one foot pushes while the other foot grabs the ground then pulls. the following foot should arrive just as quickly as the foot that leads.
*one foot should always be light on the ground, and the other one is strong and flat. unless you are close enough to wrap your arms around your opponent.
*your body should never sit in one place for more than a few seconds at anytime in the fight. the same with your hands. and the same with your head and feet.
*your feet should explode at the opponent every time you attack him, unless you are trying to draw him into a trap.
*attacking the opponent, it is best to attack in a very small angle to his outside leg (example if he has his right foot in front, you should attack toward his right leg, but not enough that he might think "the guy is angling me!"). the angle should be so small he does not notice.
*when you retreat, you use the same small angle, unless you noticed the opponent is making a deep attack, meaning he will end up where you are standing if you move back. in this case you make a sharp step to your side so you end up beside him. this will give you a better angle to counter attack than from in front of him.
*when you shadowbox, your retreatings are shorter in distance than your attackings. the attacking footwork should be capable of covering a far distance in a short time (and keeping good balance), but you still train to attack short distances.
*when making a thrusting movment, empty handed or with weapons, land your attack before the foot touches the ground. this will put your blade deeper into the opponent, and help you penetrate tight places like the ribs.
*when attacking your foot should never come above the ankle unless you are planning to jam the opponent or shield a kick or fake him.
*when you are sure you are faster than the opponent, and you have time, it is better to stay in place and evade with your body or head than to move out of the way. it is faster, and you are already close to the opponent so you can strike him while he is attacking instead of later.
i think that is enough to help. if you want to learn more advance stuff you will have to visit me and train with me. >)