Striped Summer Dress

On my last night in Hawaii I wore this striped dress. The bright colors scream summer and it is lightweight and comfortable. The dress is strapless, but I wore a short sleeve cardigan with it because restaurants are always chilly with the air condition on.

 Dress:  Derek Heart via Kohls
Cardigan:  Mossimo via Target

The dress hits above the knee and the purple strings on top can be tied any way you like. I have trouble keeping them tied, no matter how I knot them they always come undone! It’s not a drawstring, it’s just two strings that are stitched to the center. They also have little silver sparkly balls at the end before the tassels. Anyone have any tips on keeping these kinds of strings tied?