Home-decorating television shows and shelter magazines have many Americans dreaming about inviting an expert interior designer into their homes.

It looks so effortless when a popular designer arrives in a whirlwind of creative ideas and quick-working craftsmen. By the end of an hour of cable TV, he or she has transformed a hopelessly drab home into a stylish oasis.

But what’s it really like to hire a designer? How can you make sure it’s a successful — and not too expensive — collaboration?

As with a good marriage, says interior designer Phoebe Howard, the relationship between designer and homeowner is about communication, trust and respect.

FINDING CANDIDATES

Many homeowners find a designer by asking friends whether they’ve used one. Designer Cathy Davin, founder and president of Davin Interiors in Pittsburgh, says new clients are often referred to her by previous clients.

Others discover her online, she says. Interior designers generally keep a portfolio of photos of rooms they’ve designed on their websites. Browse through as many as you can in your area, noting photos that fit with your vision for your home.

Training varies: An interior designer “typically has a bachelor’s degree in interior design, and in several states must be certified,” Davin says. They can collaborate easily with engineers, contractors and architects, and should have a full understanding of color, proportion and other elements of design.

A decorator “might be just someone who has a flair for decorating and wants to hang up a shingle,” Davin says, and it’s possible their style will fit perfectly with yours. But they probably won’t have as much training as a designer.

The American Society of Interior Designers (ASID) offers a database of certified members that is searchable by location.

As you meet with potential designers or decorators, see who makes you feel comfortable, Howard says. You’re going to “open up your personal space” to the person you hire, so along with vetting their work, make sure your personalities mesh.

DISCUSSING MONEY

Howard, who is based in Florida, says a good designer should be able to tell you whether you can have what you’re envisioning for the money you’re able to spend. Be realistic and clear when discussing your budget.

Design fees vary around the country, but Davin says they tend to range between about $4 per square foot (for limited services like choosing a room’s color palette and furniture layout) to $10 or more per square foot for full project management.

Get cost estimates in writing and be sure you know exactly what is included. If you make any changes to a project after hiring a designer, get those adjustments in writing as well. The folks at ASID suggest keeping a folder with printouts of all agreements and correspondence about your project.

Extra calls or extra meetings cost money and slow the project down, so have notes ready and be prepared each time you call or meet with your designer.

AGREEING ON STYLE

Davin suggests starting with a meeting at your home with all decision-makers present. Couples should try to work out disagreements before sitting down with the designer; experts can be good sounding boards but they won’t want to take sides in a battle.

As you make design choices, Howard says, do your homework: Touch the fabrics and study the colors to be sure you like them. Comb through websites and magazines, showing your designer what you have in mind.

And trust your instincts: If a designer or a particular decision really feels wrong, don’t go with it. But also remember that you’ve brought in a professional for their creative input.

SHARING CONTROL

Do “get yourself to a certain comfort level, because you have to take the leap of faith,” Davin says. “A lot of people’s fear is that they’re going to end up with this crazy living room that doesn’t feel like them at all.”

But if you’ve taken time to choose someone who shares your taste and understands what you want, then “allow them to stretch you and push you” at least a little, she says.

Discuss timing. Design projects can move slowly. Davin says redecorating a master bedroom or family room can take at least three months. Design and decorating work for a home that’s not yet built might take 18 months or more.

The wait can be frustrating, but also useful: Your vision for the project may evolve as you work with a designer, so you might be glad to have some extra time to make choices.

Schedule a big project for a time when you can give it your full attention, ASID suggests.

STAYING FLEXIBLE

When choosing a designer, be sure to ask previous clients how the person handled changes or challenges.

“It’s impossible to install a job of any size without something going wrong,” Howard says. “Something’s going to break. Something’s going to be measured wrong. . Things happen and things get fixed.”

Try not to make too many changes, since that can increase the possibility of confusion and mistakes.

If a problem arises, it’s best to cool down before approaching the designer. And at the end of the project, Howard advises clients to leave home during the final installation work.

“The installation is the moment that the decorator worked for months and months and months on,” she says. “They need to have their space to kind of make a mess and get things done.”

So rather than critiquing the project when it’s only partially installed, she says, wait for the “red carpet moment” when the finished product is revealed.