since you didn't give us a time scale i can't sugest anything but the basic method.
keep it simple, bold and fun.
were possible make a shape change and or colour change.
props work best for focus.
rope is great, so many easy tricks you can do with little or no moves.
most kids props can be made in an afternoon and can be learnt in 5 mins, i say learnt not performance proficient, just in case someone takes excemption.
