New York — Teen-agers can make extra money during Christmas vacations either by finding existing jobs they can do or by devising their own jobs. The trick, says Ilene Jones, author of ''Jobs for Teenagers'' (New York: Ballantine Books, $2.25), a paperback self-help manual, is to know how to make the connection with the jobs that are always there to be done. Here are some of her suggestions:
Begin now, during the fall, to apply to stores for vacation jobs. If you are at least 14, you are eligible for the necessary working papers. Request these papers from your high school or from your state labor department.
If you don't already have one, you will need a social security number. Obtain this by applying to the social security office in your city. You must submit a copy of your birth certificate.
If you are seeking work in a store, go directly to store managers or personnel departments with your working papers, social security number, and resume in hand. Even for short-term employment and even if you have not worked before, a resume that includes references is reassuring to potential employers.
In writing this, think hard about your past activities and accomplishments. Were you a boy or girl scout, a leader at camp, an organizer of a club? Have you worked on a school prom, worked in the school library, debated, done any community work? Have you baby-sat or dog walked? Are you good with people? Or good in math, or artistic, or clever with your hands? Everything counts. Let people know you have something of value to offer.
One high school senior, after listing his name, address, and telephone number , said on his resume, ''I have never had a paying job before, but here is what I am like: I made it through 11th grade with passing grades. Help with housework at home. . . . I'm good with my hands and am always happy working with my hands. I am quiet, but I seem to be pretty well liked by people. I am willing to try hard.''
He listed his science teacher and Sunday School teacher as references, and he gave the dates and times he would be available for work. Sometimes the teen-ager prefers to ask former employers, the school principal, coaches, or church ministers to write reference letters in advance, attaching copies of them to the applications.
If you are a self-starter, you can find plenty of innovative ways to employ yourself and raise some cash during the holidays, Mrs. Jones says.
If you are artistic, start a gift-wrapping service. Invest in Magic Markers, different papers, yarns, and ribbons, and then charge according to the cost of materials, the success of your design, and the time involved in executing it. Offer, for an extra charge, to pick up and deliver the packages. Mrs. Jones suggests that charges could run from $1.25 to $4 a wrapped package, depending on size and complexity.
If you don't mind cold weather, ask about a job at places that sell Christmas trees. In most cities, trees have to be walked to apartments or homes. If you set the tree up in its stand, there could be additional tips.
If you have helped decorate lots of family Christmas trees, offer, for a fee, to decorate the trees of others. To some busy people, particularly those who purchase 12-foot-high trees, this is a job they may like to pay others to do. A Christmas-tree decorator-for-hire could probably charge from $2.75 to $3.75 an hour and have fun, too.
At the end of the holidays the same trees will have to be undecorated and the same clients could be willing to pay the same hourly rate to have ornaments safely packed away.
If you don't mind the elbowing of the crowds in stores, hang out your shingle as a Christmas shopper. Plenty of busy professional people, shut-ins, and dual-career couples might welcome a shopper who would pick up specified items - and they might pay from $3 to $4.50 an hour for the convenience.
Entertaining opens up more opportunities. If you have cooking skills, offer to do Christmas baking for families or to cook your special dishes. Families often need a general helping hand at parties, too.
One enterprising teen-ager with kitchen skills offered a series of holiday cooking classes for children from 5 to 8 years old. At a cost of $4 a session for each child, she taught the youngsters how to make holiday cookies, cakes, candies, and gingerbread men - and even included a session on making tree ornaments of play dough and baker's clay.
Teen-agers can always advertise their baby-sitting services, and many offer to be a mother's helper at children's parties.
How do you get your services known to people? Tell people about yourself. Print up cards or announcements to put on supermarket-, shopping-mall, or apartment-house bulletin boards. Mimeograph fliers. Advertise in the paper, and make sure friends tell other friends.