At a carnival or Mardi Gras parade, a costume has to survive a long wait on a cold kerb and a scramble for whatever the floats throw. A thin costume sized to go over a T-shirt disappears once the winter coat goes on.

The kids' carnival costumes that hold up best start in your child's wardrobe. Use a hoodie or tracksuit as the base, add one homemade detail that makes the character, and leave room underneath for warm layers.

Build toddler costumes on a hooded sweatshirt

Between about one and three, comfort decides whether a costume stays on. Toddlers tend to tear off masks and headbands, so put the character on a hood they know, and choose separates over one-piece suits for quick nappy changes.

Bear or bunny with ears on the hood

Tonal dressing, head to toe in shades of one colour, turns a plain tracksuit into a bear in brown or a bunny in white. Stitch felt ears to the hood and a pom-pom tail to the seat; felt doesn't fray, so it needs no hem. It suits the youngest, who already nap in these clothes.

From behind, the look reads as a plain tracksuit, so make the ears big. Check that every piece is sewn on tightly, because anything that pulls loose tends to end up in a toddler's mouth.

Ladybird or bumblebee in colour blocks

Colour blocking, pairing large areas of solid, contrasting colour, turns basics into an insect: a red top with black felt spots makes a ladybird, and a yellow one with wide black stripes, a bee. A toddler with a strong favourite colour is the natural fit.

Wings catch on pushchair straps, so leave them off and sew felt antennae onto the hood. Check the fit over the snowsuit; a sweatshirt a size or two up slides over it and keeps the colours on show.

Give four- to seven-year-olds a character to play

Between about four and seven, children want to be someone and act the part. A costume works when they can run and climb in it and its key piece survives being pulled off again and again.

Pirate built around a striped shirt

A striped top, the Breton shirt that began as part of the French navy's uniform, is half a pirate already. Add a waistcoat and a scarf knotted at the waist, then roll the trousers up over wellies. This one is for children who like a loud, physical role.

An eye patch cuts off the view on one side, which matters in a crowd, so paint one on. Check the headgear for cold days; a bandana tied over a woolly hat keeps the look and the warmth.

Superhero with a short cape

Give a one-colour tracksuit a felt emblem your child designs, then add a cape cut from a fleece remnant. It suits children who'd rather invent a hero than copy one from a screen.

Keep the cape no longer than the back of the knees so it doesn't drag through slush or trip a running child. Fasten it with hook-and-loop tape that pulls apart if the cape catches, instead of a tie at the throat. Check that it fits over the winter jacket.

Let children aged eight and over style their own costume

From about eight, many children would rather look clever or stylish than cute. Let them plan the look from their own clothes and a parent's wardrobe, because a costume they styled themselves gets worn.

An eighties workout look

The aerobics style of the eighties is mostly in the drawer already: leggings, an oversized sweatshirt worn off one shoulder over a long-sleeved top, a headband and leg warmers. Colours that clash on purpose are the point. It's the pick for children who'd hate a full costume but like a bit of attitude.

Leggings alone are too thin for parade weather, so add thermal tights and pull the leg warmers over boots. Check what still shows with the coat zipped, and put the colour there.

A group costume with friends

Group themes suit children who go to the parade with friends or siblings. For a box of crayons, each child wears one solid colour with a felt wrapper on the chest. For a deck of cards, poster-board signs hang front and back from shoulder cords, over any coat.

Pick a theme that still works if one friend drops out, as crayons and cards do. Check that each child can take their piece off alone to sit down.

Plan the costume around the winter coat

In most traditions, carnival ends on Mardi Gras, the day before Ash Wednesday, which falls in February or early March. In much of North America and Central Europe that means late-winter weather, and standing still on a kerb chills a child faster than walking does.

Make the costume the outer layer, not something hidden under the coat: capes and ponchos go over a jacket, and ears stitch onto a woolly hat. Underneath, use wool or synthetic thermal underwear; cotton stays damp after a run along the route and turns clammy.

Keep hems at ankle height or shorter, because a gown that reaches the ground soaks up slush. Warm boots beat any costume shoe, and gloves in the costume's colour carry the look to the fingertips.

Pick one accessory that carries the look

One strong accessory does more than a bag of props. Swords and wands get dropped in a crowd, while a hat or a belt stays put.

Face paint does a mask's job without narrowing your child's view or getting damp from breath in the cold. Use paint sold for use on skin, and test a small dab on the inner arm the day before to check for a reaction.

A crossbody bag in the costume's colours keeps hands free for catching sweets. Reflective tape on the back of the coat makes your child easier to spot in headlights after dark.

A dress rehearsal at home a few days ahead, coat and boots on, settles the details that spoil a parade day:

• Your child can sit on a kerb and raise both arms without anything pinching.
• Children out of nappies can manage the costume alone in a portable loo.
• Your phone number is written inside the coat or on a wristband.
• A plastic bag in your rucksack holds dry socks and gloves.

Let your child pick the character, then pull every piece in its colours from the wardrobe before buying any felt.