What age group is this costume for?
Preschool and Younger
Elementary School
Middle School
High School & Beyond

Estimated time required to make this costume:
minutes to hours; variable as People

Difficulty level:
Quick and easy - no sewing required
Almost as easy - some sewing

Items you will need: (Hit your return key to start a new line)
If your child is easy to please (lucky you!) scout around your home base or borrow items from neighbors (return in good condition). This is more like a Category with unlimited possibilities to portray the Adult world, miniaturized, caricaturized...:

Consider hats, dresses, sports coats, old tuxedos, team shirts, bowling shirts, Hawaiian shirts, sequined/frilly dresses, boots/shoes, gloves, clip-on ties w/loud prints, eyeglasses w/lenses popped out, furry stoles/shawls (not too long), jewelry, purses...pink curlers, bathrobes n' fuzzy slippers, hair spray, glitter dust, ordinary lipstick and makeup pencils...overalls n' watering cans, lab coats n' toy stethoscopes (docs, nurses, vets), law enforcement officers, king or queen of Rock n' Roll, Grandma/Grandpa, used car salesman, Pizza Dude...

Instructions:
If you are going to cut or alter items, a Quest to a thrift shop or rummage sale is great fun for scouting out possibilities! Looking at the odd items available may trigger ideas for something Way Fun and unusual.

Hemlines need to be short enough to facilitate easy walking, vs. tripping...so some hemming or at least cutting may be necessary. It's worth the extra time to hem it if the garment will be saved for a Costume Box for rainy days year 'round. Warmth is a factor for cool-weather activities; Vision for the child and Visibility to drivers needs to be built-in features. Aside from that, let the imagination loose and have fun with creating a costume, and accessories to go with it.

Other information to consider:
Some finishing details are worth buying new: jewelled crowns, wigs, sequined belts and headbands come to mind (fabric stores sell elasticized sequin bands by the yard, with belt closures available in Notions). If you have the storage space, save some of these accessory items from year to year, or you may find yourself buying them Again.

Little People hints:
If a child is going to wear an outfit to a school party, Be Kind and make it something that the child can get in and out of easily, fairly un-assisted, allowing easy access to Bathroom, and not too warm to wear indoors (or they will be out of costume when cameras are clicking).