The something old represents continuity, something new offers optimism for the future, something borrowed symbolises borrowed happiness, something blue stands for purity, love and fidelity. Subject to believe brides did not always wear white, it was only when Queen Victoria married Albert that she insisted on wearing white rather than blue.
Other Scottish traditions are heather in the brides bouquet and there are several traditions to bring good fortune such as; an old silver sixpence is placed in the brides shoe, another custom is for an older married woman to wash and dry the brides feet, and for the father of the bride to throw coins out of the car as the bride steps out (wedding scramble or 'poor-oot') for the children to collect.
Another tradition is when the correct date is set and the wedding plans are announced the bride-to-be and groom exchange gifts 'the wedding Sark'. The bride pays for the grooms shirt and the groom pays for the wedding dress, sounds like a great tradition to me, look out Chanel!