are the laces not looped through the grommets? If not, check this website for instructions on how to lace it up: www.waspcreations.com/howtol.htm

If they are, and you just need to tighten it, it helps if someone can assist you. But if not, reach around and grab the strings which form an X at the very top or the very bottom. Repeat, working your way up (or down if you started at the top) until you reach the middle. Pull on the strings in the middle and use your other hand to told on to them. Then start at the opposite end and repeat.