By implication, an antidote to the maladroitness, the maladaption, the clumsiness of the shy is simply learning to dance. Dance is poetry, it is economy of motion, it is the greatest return for the least effort. It is a doorway to escaping the confinement of your ego-bound self, of becoming part of a transcendent organism, a group. It is flight for the earthbound.
Dance presence represents a mind set, an attitude, a bearing that communicates confidence and sense of direction on the dance floor. It means intuiting where the other dancers in your radius of action are, your position and motion relative to them, and anticipating how your movements will interact with them. Presence, life presence is the same, generalized to Real Life.
Couples dance unfolds the mysteries of touch, of subtlety, and balance. Holding a dance partner glides you past the "sweaty palm" nervousness of actually touching a woman, and swinging your partner imparts the feeling of give and take, of balance and flow.
The simple line dances are easily learned, and mastery of couple dances, folk and square, even ballroom, follows with practice. The sense of accomplishment at getting through an easy couple dance for the first time, a "Danish Masquerade" or "Road To The Isles", makes it all worthwhile, and the sheer fun of it is an extra bonus.
Most areas of the country have folk, contra, and square dance groups. Listings of times and places may be found in local newspapers, or you can enquire in the rec.folk-dancing Usenet newsgroup on the Net. The dansegypsy page gives many links to folk dance groups across the country.