For a more casual beach-y version of the gorgeous Versus dress that Jessica Szohr wore in the February issue of TeenVogue, all you need is a long (but not too oversized in width) white tee-shirt in plain cotton, a pair of strong scissors, a ruler, a pencil, and about 15 safety pins.
Edit the neckline and armholes to fit you as you want. With your ruler, trace out six different lines the first two just under chest-level. the second two just under your belly-button and the last two right about the hem line. then Cut out the area in between each two lines (should look like long thin rectangles across front of shirt).
After that, attach safety pins as you want connecting the bottom to top of each rectangle. End result should look like this: