I made this 4th of July outfit for my daughter last year actually, so I don't have a tutorial on it.
It was super easy though.
I just took a love sleeve shirt and cut of the sleeves then made some bias out of the star knit and sewed it around the arm holes.
And added 3 strips of ruffles to the front.
For the skirt:
I just made a simple skirt and added a ruffle to the bottom.