1. Read the fine print.
Know exactly what costume pieces and accessories you're getting before buying. "We're really careful to list and detail everything that is included so there are no surprises," says McConahay, who is vice president and co-owner of AnniesCostumes.com. As with any consumer goods, read the return and exchange policy before making a purchase.
2. Predict the weather.
Before you buy, think about what the weather may be like on October 31. Leotards and tights help little girls stay warm underneath a skirted costume, McConahay says. For boys or girls, long sleeve T-shirts under their costumes add a layer of warmth.
3. Know the right size.
"Keep in mind that a children's size 4-6 is the clothing size, not an age range," McConahay says. For any costume on AnniesCostumes.com, the sizes of women's costumes are based on dress sizes, while the sizes for men's costumes are based on jacket sizes.
4. Buy early.
Don't wait until the last minute to purchase a Halloween costume, especially if you're ordering online. "Baby costumes are always bought early," McConahay says, "If you do buy early, calculate the age the baby will be on Halloween and buy the costume based on his or her expected size. "This goes for all infants and kids, too." And don't wait to find costumes for teens and adults, McConahay says. Those go fast as well.
5. Try it on.
Take the costume out of the bag well before October 31, just in case it doesn't fit. Steam or iron the costume before wearing it. "Treat a Halloween costume like an outfit for a special event," McConahay says. "That's the way to make the most of it."
6. To save money, use makeup.
Short on cash? Change your face with makeup to help the same costume look dramatically different if attending multiple Halloween events. "Be sure to follow all directions for applying and removing makeup," McConahay says. "And make sure any makeup you use is hypoallergenic."
7. Accessorize to add variety.
Add gloves or a hat to help make the same costume look different from one night to the next, McConahay says. Plus, adding different accessories is a cheaper alternative than purchasing two costumes.
8. Practice in advance.
Buy enough makeup to do it twice -- and leave enough time to get ready. "Do a practice run with your makeup a day or two, or even a weekend before the Halloween event," McConahay says.
9. Make costumes safe.
Some costumes come with masks or hats. "If the eye slits of a mask are too small to see out of, make them a little bigger by cutting them open," McConahay says. "Then use makeup to blend in the color of the mask with your skin."
10. Know your pet.
Dressing up your pet for Halloween? Understand that some pets just don't like to wear a costume, McConahay says. "Stick to something that has a cape if your pet isn't thrilled about wearing a costume."