"Step away from the MDF and put down your stencil kit," order self-proclaimed design gurus Colin McAllister and Justin Ryan of How Not To Decorate (HGTV Canada). The pair have, they say, saved hundreds of homes from style purgatory with their show and their eponymous follow-up book (Time Warner, 2005). We asked them to share how-tos for transforming the hellish into the heavenly.

S@H: Share some of the worst design nightmares you've encountered.

JR: We've gone out of our way to track down the most hideous houses in Britain. We're the saviours of style, and we're saving the world one house at a time. And let me tell you, we've seen it all. We've seen houses built without foundations that have literally fallen down. One woman fell through her living room ceiling in a bathtub!

One of our pet hates is carpet in the bathroom -- and believe me, we've seen lots of that, darling. Why do we hate it? Carpet is a home for wee-wee, a breeding ground for infectious germs, and an ecological quagmire, not to mention a design disgrace.

S@H: You've also seen lots of peach, or should we say "the shade of Satan"?

JR: We've witnessed some of the most atrocious colour combinations. Red and lilac, or green, black and red all in the same room. And yes, peach -- lots of it -- a colour that's the work of the Antichrist.

S@H: Why do you think there's so much bad taste in the world?

JR: People just don't think. Their interiors are hastily planned and end up being nothing short of repellent. Our message is to take more time and plan, rather than rush headlong into what ends up being dodgy design.

S@H: Doesn't it seem paradoxical that such decorating no-nos still prevail when there are so many resources now available to people -- like your show and book?

JR: Too much choice can be bewildering and befuddling. That's why we're always promoting the KISS principle: keep it seriously simple. The worst thing you can do is to try too hard; that's exactly how people end up with a collection of trolls and wood panelling in their sitting room.

CM: Most people adopt a higgledy-piggledy approach. They see a sofa they love on a show and a carpet in a magazine, and buy them. The result is a room that doesn't work together. If they used the same approach to dressing, they'd show up at work in a tutu, wellingtons and a crash helmet.

S@H: OK, so where do you start when performing your own decor miracles?

JR: First we figure out how much bad taste there is in the room. One is extremely bad and 10 is fairly good. If the homeowners score under eight, we bully them into doing what we want. We do listen to what they need and like, but we'll overrule them. We scare because we care. Then we work with colour. We play detective to determine the right hues for the household. We'll poke into their wardrobes, go to their favourite restaurants and pore over postcards from their travel destinations to get inspired.

CM: But we use moderation. People who follow fashion can become fashion victims. You might find yourself inspired by a country or colour, but when you go overboard, your home starts to resemble Disneyland.

JR: We build the room layer by layer, but really, once you've stripped away dodgy carpet and lilac walls, you're halfway there.

S@H: And no peach.

CM and JR (together): No peach!

CM: And ditch the avocado, too -- unless you're making guacamole.

Decorating Dos
The How Not to Decorate duo, Scots Colin McAllister and Justin Ryan, provide these tips for creating, in their own words, "rooms that won't make you gag."

Choose tasteful colours. Consult a colour wheel to determine complementary hues. Still in doubt? "We use a lot of antique cream," says Justin. "We also like chocolate brown and beige, mint green and white, toffee and burnt umber, and khaki and gold."

Ask yourself what one thing you can't afford to change. "Whether it's the fooring or the sofa, if you're stuck with it, base a plan around it," advises Colin. "People make the mistake of dreaming up decor schemes that clash with their burgundy broadloom."

Invest in staples. "Spend as much as you can on your sofa, dining table and bed," says Colin. "These items make or break a room."