On my baby doll dress, there is a seam right under the bust. That will be the point you will cut to. ( that is , don't cut the seam, just cut to the point a underneath it.)

Also, my dress is the same fabric as tshirts. Don't think it will work on other fabrics.

Snip off the bottom hems of the dress.

Then starting from one side, cut from the bottom up to the bust seams.

The strands are about 2 cms wide.( I did not measure, just eyeballed it. Really, it's okay, imperfection adds to the look.)

When you have cut completely around the dress, pick up a couple strands in your hand and give them a tug.

Do this to all the strands. This will make the fabric curled into itself and somewhat fix the length.

Now put the dress on, stand in front of a mirror and style it.

You can do diagonal, even length, short , long, whatever that looks good on you.

For my diy, I left 3 strands in its original length and tied it together.