If you want your kids' rooms to look more like something out of House Beautiful and less like a battle zone, turn the decorating over to them. As a result, family fights will probably diminish because your offspring will take pride in the project.

"Kids treat their room with respect when they've had a say in decorating it," says Antonio F. Torrice. The San Francisco designer advocates giving children as young as 2 or 3 a substantial say in room arrangement and colors.His opinion is endorsed by child psychiatrist Lee Salk. "Designing with children helps them learn how to make important decisions and feel independent in a constructive way," says Salk.

When you give children a choice, you teach them that they can influence their environment, which builds self-esteem, says Torrice. He and his design partner, Ro Logrippo, are authors of "In My Room: Designing for and With Children (Fawcett, $22.95).

Torrice deplores the practice of furnishing a child's room to satisfy the parent's long-cherished dreams. When he's called in - usually by parents with liberal ideas - he plays games and talks with the kids to learn how they want the space arranged and what their color preferences are.

It doesn't have to cost more to do things this way, he says. There is an inexpensive as well as expensive way to provide for the communications, storage and self-expression centers Torrice says should be part of every child's space.

A low-cost chalkboard and a high-priced intercom both permit parents and kids to communicate. Self-expression can be encouraged lavishly with track lighting, a microphone and a custom-built stage or modestly by putting a curtain with windows in it where the closet door should be. Accessible storage can be custom built or made of discount-store plastic basins with hand-lettered labels on a wooden shelf.

Low-cost window shades can be installed to pull up rather than down so a child can operate them, says Torrice who is one of the few designers specializing in children's environments.

Some advice to parents to help their children feel more involved with their rooms:

- Allow your child to pick a color he or she wants and put it in the room in some way - paint or bed linens or even a desk blotter.

- Rearrange the room to make all or most of the storage accessible to the child. Lower clothes rods in closets. Install hardware children can easily grasp. Label containers so children know where things are. Ask the kids for ideas on where and how to store items.

- Create learning centers in the room to reflect a child's special interests. If he is fascinated by meteorology, hang a thermometer by the window. If she likes to collect leaves or rocks, provide a magnifying glass and a place to display finds.

- Rehang art, clock and bulletin board closer to a child's eye level.

Torrice and Logrippo seem determined to make American children aware of decorating products and services. They plan to launch an exhibit this fall that will teach children the basics of decorating. The exhibition would tour children's museums around the country. There will be information on how carpet, furniture and wallpaper are made, for example. A large dollhouse with scale model furniture will give kids a chance to design a room.

Torrice has worked out some of his ideas in a furniture collection for Childcraft Co. of Salem, Ind. The modular maple furniture can be stacked to accommodate children as they grow. A room with storage units, desk and twin beds would cost under $700 retail, according to the designer. A useful module is a tambour-door rolltop desk with a pull-out writing or play surface.