Follow these 5 easy steps for a fun-filled dayWeeks (sometimes months) in advance, children begin anticipating their birthday parties . . . and many parents begin dread-ing them. What are the right number of guests, the most-fun activities, the perfect cake? Here to help is Parenting's party guide - with kid-pleasing themes for every age, answers to sticky etiquette questions, the lowdown on loot bags, and more.Five steps to a successful day

1. Keep the party short - 1 1/2 to 2 hours at most. A typical program: 15 minutes for guests to arrive, an hour for eats and activities (or less for kids under 4 years old), 15 minutes to sing "Happy Birthday" and cut the cake.

2. Give early arrivals something to do. They can chase bubbles or fling Frisbees outdoors, or use crayons, markers, and paper inside. Says Karen Wood, a Lafayette, Calif., mom, "I put big mounds of Play-Doh on the kitchen table and let the kids go at it."

3. Plan more activities than you think you'll need, so you're not caught short. Try classic indoor games like musical chairs or Twister, or outdoor fun like relay races or leapfrog. "When the kids got a little restless during my son's third birthday party, I blasted some tunes on a boombox and got them dancing," remembers Dan Rowen, of East Hampton, N.Y.

4. Don't overthink the food. Kids eat less, and faster, than you might think. "They need to burn energy first, and then they'll sit and eat," says Scott Thompson, senior program director of the YMCA in Berkeley Heights, N.J., where he supervises sports parties. Serve nonmessy nibbles first - pretzels, Goldfish crackers, vegetable chips - and save the pizza and cake for the finale. Provide food for the adults, too: mini-sandwiches, bagels, coffee (once kids are 5 or 6, grown-ups usually don't need to stay).

5. Line up friends, grandparents or teenagers to help with activities, serve food, and clean up.

Shop by mail

If you can't find - or don't have the time to search out -decorations, paper goods, or goodie-bag stuff, you can probably track them down via catalog. Some to try:

- Birthday Express. All the fixings for 43 theme parties: cups, plates, party hats, favors. Lots of armchair inspiration, from Looney Tunes to Madeline, jungle fun to swashbuckling pirates; (800) 424-7843.

- J&A Handy Crafts. Project ideas, from science to art, plus an array of art materials; (516) 226-2400.

- New York Cake & Baking Distributors. Bakeware of all types, from cookie cutters to cake pans in unusual shapes; (800) 942-2539.

- Oriental Trading Company. Excellent range of low-priced party favors (wacky sunglasses, groovy pencils, and so on) that kids love; (800) 228-2269.

- S&S. Arts, crafts, games, and partyware, including stuff for themes older kids may like, such as rock and roll or luau; plus trinkets sold in bulk; (800) 243-9232.

Take the cake

Forget about fancy batters, fillings, and frostings. Choose crowd-pleasing chocolate or vanilla and invest your energy in decorating - but don't worry about it. "Kids appreciate anything colorful and fun," says Lisa Sofer, president of New York Cake & Baking Distributors. Her tips:

- Put basic baking pans to imaginative use. For the younger crowd, build a wiggly caterpillar by using two bundt pans. Slice the baked circles in half and alternate them, up and down, for the S-curves of the critter. Or construct a choo-choo train by baking in miniloaf pans; place them in a row and use cookies for wheels.

- Arrange cupcakes on a large tray into a shape - the number 2 for a second birthday, or a cheery face, using different-colored frosting for each feature.

- Instead of icing the cake sides (often tricky), just march tall wafer cookies all the way around.

- Use cookie cutters as stencils. Spread frosting on a plate, press cookie cutter into frosting, and stamp design on the cake. Color in the shape with frosting in a pastry bag or store-bought frosting tubes.

- Invite partygoers who are 4 and up to help decorate. Set out bowls of food-colored frosting and toppings - M&Ms, shake-on sugars, candy hearts, gummy worms, minimarshmallows - and let them go to town.

- Ice-cream cakes are a tasty alternative to baked ones. Make it yourself for the freshest flavor.