The jig has many permutations, but most popular is the double jig, which begins with the basic rise step. To do this step, raise the right foot up and to the front, then hop with the left foot while lowering the right. Finish by lifting and lowering the left then right foot in quick succession. The movement is fast, repeated three times within a bar of music. The up and down swaying movement is revealing of the inventors of the jig, who were sailors imitating their ship's rocking motion.
The reel has a basic sidestep: First, bend the right leg back at the knee, and then swing it forward and step down onto it. From this position, move to the right, alternating feet. Step with the right foot first and keep it pointed forward as you move. After seven steps, repeat the first movement, lifting the right foot and swinging forward onto it. Shift back to the left foot and then forward again in a rocking motion. Reverse and repeat the rock, starting on the left foot. Then lift the left foot, reversing the whole step to the left.
Traditional Celtic dance music has many styles. Prominent are the jig, the reel and the hornpipe. There are variations, such as the Strathspey, a more strongly accented hornpipe, as well as the use of European waltzes or polkas. The most important part of the music is the meter, which determines how many beats are in a measure of music. In terms of the dance, the meter determines the feel of the music (and the number of counts, if you're counting steps).
The jig is in 6/8 time, which means it may be counted as a fast six, or a slow two (two groups of three, splitting the six beats in half). Either way, the count is grouped by threes. This gives the jig a lilting, rolling feeling, perhaps telling of its nautical origins. A reel is in 4/4 time---there are four beats in a measure. The reel is faster than the jig and has a straighter meter, although at fast speeds the notes are often clipped and swung. The hornpipe is also in four, but while the reel has strong beats on the one and three counts, the hornpipe has strong beats on two and four. This makes the feel of the hornpipe slightly counter-intuitive and so potentially more difficult to learn at first.