Traditionally, the mother-of-the-bride has to be the first one who gets to select her dress for the wedding. The rule of thumb is that mom should be allowed to select a style in which she feels comfortable, while still being in sync with the mode the bride has set with the selection of her gown.
Ask for her opinion. Get to know her taste. This will save many an argument. Get a pen, paper and catalog and go through with her to find out what style she likes. Find a dress that is flattering to her shape, size and taste.
Formal or informal. If the wedding is going to be formal, the mother of the bride should wear a floor or tea-length dress. Also, for a formal wedding, gloves are in order for the mother of the bride. If the wedding is semi-formal or informal, she has more flexibility in her choice of dress length.
Time of the wedding. A daytime wedding requires a short dress, although some mothers like having an opportunity to wear a long gown.
Color. Do not choose white attire for your daughter’s special day. The dress should never be the exact same color as the bridesmaids, but should go with the party colors rather than standing out. For example, if the bridal party is wearing emerald green dresses, your dress should be a lighter shade of green; almost a mint green.
Style. The most popular choices are between a skirt or trouser with a jacket suit or a dress. The dress is usually floor length or tea length, depending on the formality of the wedding. If you choose to wear a jacket suit you have to decide if it’s going to have short or long sleeves, depending on the weather.
Age. Dress in terms of age only if it is her style and it gives the look you and she wants. Some dresses are very matronly, so if she prefers to dress a little younger, then do it.
Size. Be sure you know your exact dress size and measurements. Have your measurements taken by a friend or professionally if necessary.
Talk to the mother of the groom. The mother of the groom should also be involved. You should make sure to let her know the colors you will be wearing so she can coordinate with you and not end up wearing the same dress! She will appreciate your help because she is going through the same problems as you picking out mother of the groom dresses, except it is customary for her to defer to your choice first so it is that much more difficult for her.