Start by asking and answering basic questions. What do you want to accomplish? More living space? An extra bedroom and bathroom? An update for tired old rooms? A new layout to correct dysfunctional floor plans? Will you use remodeled or new space enough to justify the cost? Will you raise your home’s market value? Should that even matter to you?

Get design help, and put together a serious plan. Architects, house designers, and kitchen and bath designers—each with varying strengths—can convert your ideas and wish lists into a detailed plan with a rough budget.

Hiring a contractor who can turn ideas into reality—as painlessly as possible and at a fair price—is the most important step. Start by consulting customer reviews here. As you make a list of prospective contractors, ask many questions of past customers and pros in the field—among them: Does the company do the kind of work you have in mind? Does it follow plans? Does it get the work done when promised? Does it help you find low-cost solutions? Does it stick to agreed-upon prices? Does it solve problems promptly? Do workers communicate effectively? Does it limit disruption to your daily life as much as possible? Are the results as professional and attractive as you would expect? Is it flexible enough to make changes at a reasonable cost if you change your mind?

Meet with at least three (but preferably four or five) candidates, and go over your plan in detail, while asking pointed questions about their experience and credentials as well as potential problems—from your perspective and the contractor’s. Yours will be a close relationship, so imagine what it would be like to work with this person for weeks or even months. Afterward, check out key credentials, including references, licensure, insurance, and complaint history.

Checkbook’s undercover shoppers found a wide range of pricing for two different remodeling projects: from $113,000 to $205,000 for one job and from $26,000 to $61,000 for another. Moral: Get multiple fixed-price bids. Also, don’t assume that there’s any relationship between price and quality. Many contractors do great work at low prices.

Pick a winner; then get a formal contract. Good contracts cover everything from payment terms and deadlines to who does the work and warranties.

There’s much you can do to help your project run smoothly. Communicate with your project manager every day. Deal promptly with surprises. If work isn’t done to your satisfaction, don’t pay until the contractor makes it right.