8 Basic Clogging Steps

TOE Touch the ball of the foot to the floor making a distinct sound with the toe tap only.  The heel should remain off the floor.  Usually implies shifting your weight onto the ball of that foot.  (Referred to as a "Touch" when no weight is transferred)
HEEL Implies that the ball of the foot is already resting on the floor and carrying your weight.  Snap your heel down, sounding only the heel tap, shift your weight onto the entire foot.
STEP Place entire foot flat on the floor, sounding the toe and heal taps at the same time, shifting your weight onto that foot.  (Referred to as a "Stomp" when the step is strongly accented.)
ROCK Implies that your foot is to be placed slightly behind your center of gravity.  Step your weight back onto the ball of the foot, sounding only the toe tap, lifting the other foot off the floor.
BRUSH A kicking motion in which only the toe tap sounds.  The ball of the foot strikes the floor a glancing blow and the foot continues moving in the direction of the kick.  (i.e. Brush Out, Brush Back, Brush Across.)
DRAG With your foot flat on the floor and your knee bent, spring up slightly and straighten your knee, letting the momentum drag your foot backward about half the length of your foot.  During the drag your weight shifts onto the ball of your foot, but your heel just barely looses contact with the floor.  there is no distinct tap sound.
SLIDE A skipping motion which is the forward counterpart of the DRAG back above.  With your foot flat on the floor, bend your knee slightly and roll your weight up onto the ball of your foot, raising your heel off the floor.  Let the momentum slide you forward on your toe tap about half the length of your foot.  Immediately snap your heel down making a distinct sound with the heel tap.  (Referred to as a "Hop" when the skipping motion is exaggerated so that foot clears the floor completely.)
DOUBLE 
TOE
A short brush forward with an immediate brush back and a slight bend of the knee.   Only the ball of the foot should touch the floor and there should be two distinct sound from the toe tap within the space of one beat of music.