Surprise Party for a 6 Year Old

A real big surprise would be to not invite her to it, or to not invite anyone else!! I presume she means that the theme should be a surprise? It depends a lot on what resources you have, the choice of locations, the amount of money/assistance available. You could let everyone bring their pets... or their grans... or just base it around something she's particularly interested in, but, obviously, not the same theme that all her little friends have opted for.

Give her 12 gifts for every month in the year until her next birthday teaching her some lesson. For example buy some good looking candles and say that "Candles are the best example for sacrifice they give light to others by melting themselves", "Pen with a gold Nib - Not only your spoken words, your written words should also be gold", "Laughing Buddha - Look at him for 20 seconds whenever u r sad, u will forget all your worries", "Her name on an Ice Berg - Her life must be cool like the Ice berg", "Solar Calculator - Works until the existence of sun, she should also lead such a life", "Roses - if u want to reach a good position u have to pass through many obstacles", "Perfume - Share your happiness with the people beside you" and so on.., but since she is only 6 year old you have to do something more for her, she may not be able to understand all these things, so wake her up at night 12 'o' clock, take to beach, arrange a small cake cutting party with her friends, give her the gifts, carry a handy cam, take her to the places where ever she wants to go.