According to the May 2011 newsletter from ApparelMag.com, "on average, fabric represents 50% of the cost of producing a garment, making decisions as early as possible in the process and optimizing estimations saves both time and money".
Therefore, when producing garments, it is important to be careful when evaluating fabric consumption. Make sure to use a good pattern maker and good markers. You most certainly do not want to have high fabric wastage. High fabric waste eats at your profits.
My suggestion is to consult with a pattern maker (the best place to find a pattern maker is the pattern makers group here on FIN).
You may also want to check out the fabric utilization term to learn more.