Choose costumes that are appropriate for your pet's size, build and temperament. For example, a pug may need a costume that's small, but with a roomy chest and shoulder area. A bulldog needs a costume large enough for the neck, but not so large that the dog trips on it. Some breeds can be "thin-skinned" and ticklish, and may never get used to costumes. Follow the same rules for Cats.

If your pet has never worn clothing or a costume, start with a hat or bandana.

Put the costume on your pet for a few minutes a day and build up the amount of time your pet tolerates it.

Assure that costumes do not limit your dog's field of vision.

Never leave a pet unattended in a costume.

Avoid costumes with small pieces such as beads that can be swallowed.

Make sure that the costume fabric will not overheat your dog.

Assure that elastic bands do not become uncomfortable. Even a mildly snug elastic band may be uncomfortable after an extended wear (over 30 minutes).

Monitor your dog frequently for signs of physical discomfort, such as moving or walking in a stiff or unusual posture, reluctance to walk, or pawing/biting.

Watch for behavioral signs that a pet is becoming stressed by the costume, such as increased agitation or defensiveness
 If your pet shows any of these signs...Take off costume immediatly.