"As a sister missionary, you become destined for many wonderful experiences and blessings because you have chosen to serve the Lord in this manner. Here are some ideas that might help you in your calling.
First, examine your attitude. It shows in all you do, whether it is negative or positive. This is very important. I saw several sisters lose much of their effectiveness because of a negative or hesitant attitude. Sister missionaries are sometimes plagued with questions such as “I wonder if I should be here,” or “Perhaps I should have married instead.” These are questions that must be given deep consideration before the mission and then placed aside after one is out in the field. Once the decision to be a missionary is made, remind yourself that you are glad to be an instrument in the hands of the Lord for this short period of time; strive always to be a faithful handmaiden of the Lord Jesus Christ.
The principle of sacrificing in order to be worthy of blessings is not new. In section 97 of the Doctrine and Covenants we read: “Verily I say unto you, all among them who know their hearts are honest, and are broken, and their spirits contrite, and are willing to observe their covenants by sacrifice—yea, every sacrifice which I, the Lord, shall command—they are accepted of me.” (D&C 97:8.)
One of the most apparent sacrifices that a sister must make grows out of the fact that in many ways proper physical appearance is more difficult for her to maintain than it is for an elder. There are missions in the world where the sisters still ride bikes, and though the elders do too, it’s a bit easier for them to participate in or come away from such an experience presenting a proper picture.
Appearance is one area where a sister must sacrifice the tendency to rationalize by claiming she has neither the time nor the opportunity to keep herself neat and clean. It takes ingenuity and planning, but it can be done if she sees its importance.
The Holy Ghost works only in a certain type of vessel. The Spirit may work through an individual who is pure in heart, but it works at its greatest strength through a person who is in all things pure and clean.
If a sister can laugh at those times when a radiant appearance is impossible and work smartly behind the scenes to look her best when it is possible, she will feel better herself, she will look better to others, and the Spirit will be better able to work through her, for she will be a pure and holy vessel, inside and out.
A good guideline to follow is this: Never cheat the Lord by spending too much of his time on the way you look, but do remember that physical appearance and health are very important for a successful mission. The sacrifice of time and thought will reap its rewards.
The third point to realize, therefore, is that there are many things a sister missionary should consider besides those general commitments that all missionaries make. One such covenant involves pledging to honor and support the priesthood authority over you (even though this authority be administered by an elder who is younger and less experienced). This is an important lesson to learn, for the line of authority is an eternal principle of the gospel and of the home.
Another suggestion might be to covenant that you will work so that you never have to be excused because you are a sister missionary--to try in all things to be an example and to be above reproach.
It is by adjusting your attitude to one of complete trust in and devotion to the Lord, by making the necessary sacrifices, and by covenanting with the Lord to do certain things that you will have the privilege and the right to the influence of the Holy Ghost.
I know that if you will do these things, you will find emerging within yourself a strength that will help you bear up under many hardships. You will gain an insight into the gospel that will bring peace to your heart. And you will have an aura of femininity and a serenity about you that no charm course or time spent before the mirror could ever produce. All this because you will be acquiring qualities that will help you to fulfill your mission in this life as well as in the eternities.
Exercise for a few minutes every morning; then eat a good breakfast and not a piece before lunch unless you want to put on weight.
In some places you can save a lot of time by eating your hot meal in an inexpensive restaurant or boarding house.
Make weekly menus and shop for as long a period as possible. This saves time and money and you will not buy as many high-calorie treats.
When cooking, make enough at one time for at least two meals.
Do not have a food fad where you eat the same things every day.
Eat at least one hot meal per day.
If you are one pound overweight, it is too much. Take it off!
Instead of stopping at a bakery for a quick lunch, stop at the store and buy a yogurt, some cottage cheese, or some such prepared, healthy food. Carry an apple or raw vegetable to tide you over until dinner. (We always carried a spoon in our handbags for meals away from the apartment.)
When invited to dinner you do not have to say you are on a diet; just take small helpings, no seconds, and cut down the next day. This way you do not offend the host, and you can still accept invitations to dinner.
Never, never eat late at night! When you come home late after a discussion and you have not had time for dinner, eat a little salad or fruit and then go straight to bed and think how much skinnier you will be by not eating a large meal until morning.
Chew gum only in the privacy of your apartment.
Elders’ most frequent complaints are about sisters’ hair. Have a neat and easy style—not too short or it will look like the elders’, and long enough so that it can be curled on Sunday and for special occasions.
Sleep on a satin pillowcase; this preserves hair style and also femininity.
Do not feel that because you are a missionary you cannot wear makeup. Do wear a minimum, but do not go completely without it.
Buy clothes that are easy to care for.
Whatever your wardrobe or climate, put on clean underclothes every day (even if it means taking five minutes the night before to rinse them out).
Do not carry one of those suitcase handbags that sister missionaries are so notorious for. Carry only the essentials in a medium-sized one, and put pamphlets or books in a separate plastic or leather case. (They will not get dog-eared this way.)
Carry a combination rain-wind bonnet, some tissues, and a couple of disposable, scented towels in your handbag. (The towels are nice for freshening up during a day away from your flat.)
Spark up those drab colors with scarves and bows.
Learn how to make those quick, no-bake chocolate cookies for branch picnics.
Do not ever slap or poke an elder.
Expect and then allow elders to open doors, help into cars, put on wraps, and start your motor bikes. Do not ignore their efforts, but do not be obnoxious if they should forget sometimes.
Have a BNTE Week (Be Nice to Elders Week) where you either cook something good or do something nice for your district. If you do this, remember that this week especially you must work like a whirlwind so no one can say that you borrowed the Lord’s time. Make it a top week in service and in work also.
Always participate with the elders on preparation day. If it is something you cannot do, then at least be there to watch or cheer. This does wonders for mutual respect between elders and sisters.
If you get depressed, set aside a little time that day to do whatever raises your spirits. For example, spend extra time on your hair, take a long shower, schedule a time for meditation, and then pray earnestly for help from the Lord. Lose yourself in the Spirit and work very, very hard.
Read the whole article here: https://www.lds.org/new-era/1972/10/a-letter-to-girls-about-lady-missionaries?lang=eng