So try on the shirt. measure around where you want the neckline (shoulder line?) to be. Since it's off the shoulder i measured 8" from my shoulder and cut straight across. Pin where you're goin to cut first, to avoid the two pieces separating and becoming uneven.
next, put back on the shirt and measure how long you want your puffed sleeves to be. again, i measured 8". this included seam allowances, and allowance for the ruffle.
Now your shirt should look something like this. the green lines i drew on the picture show where the elastic will be. first, hem the neckline and sleeves. dont forget to include the top part with the button so that it wont be able to reopen.
Now you measure your elastic. the piece for the neckline will be the length of ONE of the sides of the shirt, ie, the front OR back(they're the same length, duh. do the same for the sleeves (elastic as long as one side of the sleeve so that its half of the entire width to go around your arm.do that same for the waist.
now with the elastic about an inch away from the hem, use a zig zag stitch to attach it to your neckline and the edges of your sleeves.stretch the elastic as far as it will go as you stitch, as this will cause it to bunch up and create that awesome ruffly effect. the great thing is that the elastic will stretch to twice its size, so don't worry about your elastic being too short
after you do this for the neckline and sleeves, stitch the elastic onto the drop waist of the shirt, which wil be underneath the last button. the drop waist will allow you to create the bloused over effect.