Be sure the vines are adequately spaced, congestion will lead to infestation and mildew problems. Wind is another potential hazard, try to reduce excessive wind shear. Over-watering is also an issue, be sure there is proper drainage and be sure you water when there is drought. Some growers will make a mound around the vine to encourage drainage, rocks and gravel will help as well. Keep an eye on the growth and react quickly to anything that is suspect - mildew, insect holes and dryness are the biggest risk indicators.