The attire of a dancer involves a very specific costume, lots of jewelry, heavy anklets, and exaggerated makeup.
Let's start with the head. The hair is usually either wrapped in a big bun with orange and white flowers wrapped around it. Or more commonly in a very long braid with flowers wrapped around the intial tie and more laced through the braid. At the end of the braid is a tie, sometimes it can be fancy with extra threads or an ornament hanging from it.
The makeup is stage makeup, meaning very thick and dark. There is a lot of emphasis placed on the eyes, cheeks, and lips. The eyeliner is very bold and eyebrows are darkened to help the audience notice the expression. Lots of powder and blush are used to give the face a clear, smooth appearance. And lips are bright red to emphasize smiles, pouts, and other mouth expressions. Also the tips of the fingers and toes are colored red to help the audience see the hand gestures and feet. There used to be a special paste, but for modern dancers any red marker will do.
The jewelry of Bharatanatyam is usually gold and full of different colored stones. The jewelry that adorns the head includes a headpiece that sits just on the hairline with a piece coming down the center. Next are two different clips on either side of the center line. One represents the sun and sits on the right side of the head, the other is the moon and is on the left. Then long earrings that are set into place at the earhole and up the length of the ear and then attached at the hair. A nose ring is worn in the middle of the nose, and can be accompanied by the usual stud on the left or right side.
The other major jewelry is worn on top of the costume and includes necklaces, belts, bangles, and anklets. There are two main necklaces that must be worn: the first is a choker, and the second a longer chain that reaches about the middle of the ribcage. Next is a belt that goes just over, if not a little above, the bellbutton region. The anklets are approximately 3-inch-wide straps that have bells (similar to Christmas bells) attached. These anklets help to emphasize the beats of the footwork. Lastly, the bangles are tradtional glass bangles and usually the color of the costume.
And now, the whole picture...
For men, it is very basic. The outfits are usually just a simple pants or a full traditional kurta with long sleeves and a sash. The makeup is the same as for women, as it allows the expressions to be emphasized on stage. The men also wear the anklets, choker, long necklace, and usually just hoop earings. A unique piece of jewelry for the men is an armband. In medieval India men would always wear some sort of armband. Sages and gurus would wear ones made of wooden beads, warriors wore gold ones(similar to the style mostly used for the dancers), and the lower classes would wear ones made of thick thread.
If a woman is playing the man's role, they will make their hair appear short and sometimes draw in facial hair.