The character of Cha Cha is "fast and sassy" with a staccato feeling that can be quite athletic. Even though the dance is often called "Cha Cha Cha", it is danced "Cha Cha".
It is very important to understand the musical timing of Cha Cha to dance it correctly. If you don't, it will always have a "frantic feeling" and fast Cha Cha's will be very difficult to dance. Cha Cha music is usually played in 4/4 time generally at a speed of 28 to 31 mpm (measures per minute). Musically it is counted: 1, 2, 3, 4, & or an easy way to remember it is: 1,2,3, Cha, Cha (a Cha is 1/2 beat).
As with all Latin dances, the steps are taken with the toes (no heels). A toe step is taken by lifting the knees that are attached to your heels (your heels leave the floor not your toes). This gives your steps and up and down feeling with your toes sliding across the floor. It is danced in a spot on the floor (as opposed to traveling around the room) with small steps (toe steps give you small steps). The footwork for Cha Cha requires distinct steps (no shuffling - shuffling is too slow and gives you an entirely different look).
Cha Cha is a Latin dance which means Cuban motion (hip action) that is a whole topic by itself not to be covered at this time. The major difference between American Style and International Style Latin is that in Cuban motion you move to a bent leg in American Style and you move to a straight leg in International Style. Latin dances (including Cha Cha) are danced from the bottom of the rib cage down. The upper body remains stationery. The foot moves first then the body follows. The Frame is compact with a slightly forward leaning position, and you are off-set slightly from your partner. The secret of Latin dancing is using equal and opposite pressure to leverage off each other and not interfere with your partners balance (also a topic by itself).
The first patterns you should learn are the "Side Basic: and the "Progressive Basic". These two figures are the basis for just about all of the Cha Cha patterns.