If you're the mother of the bride at an upcoming wedding, congratulations! You have a major part to play in supporting your daughter as she prepares for her big day. Being the mother of the bride (or the M.O.B., as she is sometimes known these days) is a role which calls for understanding, tact and diplomacy in many delicate areas, not least being the question of wedding attire. As well as helping your daughter to select her bridal gown, you have another tricky choice to make: finding your own mother of the bride dress.

As with most aspects of wedding planning, there are conventions that some couples wish to follow and others they will prefer to ignore. But if you know what the 'rules' are, you'll be better able to decide when you want to break them! And in most cases, the principles governing mother of the bride gowns are designed to allow her due precedence -- without overshadowing the bride herself!

• Appropriate color. Many people feel that mother of the bride dresses should not be white or black. In the first case, of course, it's because white is traditionally the color reserved for the bride. The second rule harks back to a time when the bride's mother could signal her unhappiness at her daughter's marriage by wearing the color of mourning.

  While such a gesture might be thought extreme in today's world, it is still frowned upon in some quarters for the M.O.B. to wear black -- perhaps simply because it might be considered bad luck. These days, however, what's appropriate is often dictated by the style of the wedding and the bride's preference -- and in an era when evening weddings are not unusual, black might be an acceptable choice.

• Coordinate with the mother of the groom. While it's customary for the M.O.B. to choose her dress first, it's considerate as well as prudent to liaise with the groom's mother in matters of style and color. This will at least minimize the risk of both mothers turning up to the wedding in the same outfit!

• Complement the dresses of the bride and bridesmaids. As a member of the wedding party, the eyes of the guests will be drawn to your outfit too. Plan well ahead with the bride to decide on an age-appropriate design and color to coordinate with their styles.

As part of the build-up such a joyous event as a wedding, choosing a mother of bride dress ought to be fun. And while finding exactly the right outfit may require a considerable expense of time, energy and shoe leather, it's a task that you can enjoy in the company of your daughter or a close friend or two, if you like. After all, the wedding will be partly your day too!