its really easy
my biggest tip is to layer layer layer
tie one layer on the bottom and 2nd layer on top to give it the "poof" dont forget to play with the colour combos and add fun stuff like ribbon strands, gems, anything you feel with give it a personal touch that no one else does
make it long-ball gown lenght but not so she trips over it she should be able to run around in it without tripping
tie on shoulder strap ribbons and your all set to go have fun!