Start with a basic tee of some sort, it doesn't even have to have anything on it. In order to make a small/medium. I needed a XL Tee... if you are not that size, follow this chart.

Size XS needs Men's Large
Size S/M needs Men's XLarge
Size L needs Men's XXLarge
Size XL needs Men's XXXLarge

First lay your shirt out completely flat.

Measure your bust, waist, hips, width of your arms, etc... and mark them out on the shirt.

Cut along the lines you have made, making very sure to allow a 1 and a half inch allowance around all sides.

Puncture holes with the tips of your scissors (VERY CAREFULLY) every 2 inches or so. about 1 inch from the previously cut edge.

Make cords by cutting strips 1 inch from the scraps you cut off the shirt in step 2. and pulling them until they roll up into cords.

Weave the cords in and out of the holes you made like a shoelace. starting at the end of the sleeve. do this to both sides with 2 separate cords. leave some slack at the end of both after weaving to make sure you are able to adjust the dress for comfort.

And you are done!

As I said, not the best tutorial because i lost the step by step pics, but if you have questions, just ask.

I really wanna see pics of ya'll wearing your versions and what you would wear with them.

Have Fun!