No-gripe grip: Grab the handle and place your opposite hand's index finger between your fingers and palm. If the index finger fits comfortably, that's probably the rip for you.
Head size: Because of their power and forgivingly large sweet spots, "oversize" rackets are best for baseline or doubles players. "All-court" and "serve-and-volley" players pften prefer midsize or "midplus" rackets.
Length of racket: Long or short? Racket length is the main factor to consider when buying for a child. and the right length relates more to the child's height and hand-eye coordination than to age.