There is very little evidence that any specific measures are helpful in preventing varicose veins. However limiting or modifying some of the contributing factors may be helpful in preventing progression of varicose veins. It is likely that exercise, avoiding be overweight and avoiding long periods of standing stationary might be helpful. You should also avoid wearing garments (socks or stockings) that restrict the blood flow from your legs. It may be helpful to avoid constipation and it may also be useful to avoid wearing high heel shoes for prolonged periods of time as these shoes mean the calf muscle is unable to provide an optimal pumping effect. There doesn’t seem to be much evidence that crossing your legs has any effect on varicose veins.