WHEN GEOFF BARTAKOVICS, CEO of the food-and-drink e-newsletter Tasting Table, decided he wanted to bulk up his "skinny-guy" physique, he approached the challenge the same way he would a business decision: with gobs of data.

Along with implementing a workout regimen, he started using a high-tech scale called the Fitbit Aria to keep tabs on his weight and body mass index; he tracked his physical activity with the Jawbone UP, a popular motion-sensing bracelet; and, at his trainer's urging, he ordered an Omegawave, a clinical-grade ECG monitor that tells him how strenuous of a workout he should undertake on any given day.

Interactive: Fitness-Tracking Gizmos

Illustration by Serge Bloch; F. Martin Ramin for The Wall Street Journal, Styling by Anne Cardenas (2)

What appeals to Mr. Bartakovics (who has added 2 pounds of muscle and brought his body fat down to 10% in the past month) is how effortless the process is. "I wear the bracelet during the day and step on the scale in the morning. The apps do all the tracking," he said. "Once a week, I spend a few minutes looking at the metrics to determine whether what I'm doing is working."

Mr. Bartakovics isn't unique in his data-driven approach; he's a fairly typical member of the "Quantified Self" movement, which has been growing at a steady clip since the term was popularized by writer Gary Wolf back in 2007. (The term might be new, but the practice is not; Benjamin Franklin famously charted his life for decades.) Quantified Selfers now organize meetups in over 80 cities around the world.

As health-tracking gadgets get less expensive and better looking, more people are jumping on board. The Pew Research Center estimates that nearly 70% of adult Americans now track some aspect of their health or that of a loved one, whether using an old-fashioned notebook or a cutting-edge gizmo. In fact, collecting data is now the easy part; what's difficult is making sense of it.

No matter what gadget you use, the basic approach is the same. Here are five key steps to ensure you get the most traction with your trackers.

1. Zero in on a goal

Self-improvement is best approached with a goal, not a gadget, according to Buster Benson, a dedicated quantified selfer and creator of the popular goal-setting site 43things.com. "What most people get wrong is that they start tracking steps, calories or sleep before they come up with a question that they're trying to answer or a problem that they're trying to solve."

2. Find the tool

No matter how specific the health-related metric, odds are there's a device or app to track it. Check out quantifiedself.com/guide for a comprehensive list (it has a dizzying 505 entries). While trackers work well solo, integrating the data from multiple devices can be especially revealing. The trio pictured in the interactive, for example, will give you a read on everything from sleep quality to body mass index to what days of the week you tend to be happiest.

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Click here to view the interactive

3. Establish a base line

So you've got your fancy new tracker and are ready to embark on your healthier lifestyle. Hold your horses. "I usually advise patients to not change anything for the first few weeks they're tracking," advises Paul Abramson, a San Francisco-based physician who goes by the moniker "The Quantified Doctor." Establishing a base line sets a marker against which you can measure future progress.

4. Make incremental change

Resist the temptation to tweak too many aspects of your lifestyle once you start tracking, suggests Dr. Abramson. Instead, conduct controlled experiments. If you're trying to improve your sleep, don't institute pre-bedtime yoga while also dropping carbs from your diet—at least not if you want to be able to tell which is having the most effect. Mr. Benson advocates setting manageable objectives (for example, splitting a goal to lose 20 pounds into two 5-pound projects, then a 10) and tracking for 30 to 60 days at a time—enough to figure out if a lifestyle change is working, but not so long that you'll get demoralized if it isn't.

5. Aggregate the data

Here's where it gets interesting. Most devices encourage you to view the data they collect using their proprietary apps or websites; while these can be helpful for goal setting, they aren't ideal for figuring out how the more disparate aspects of your lifestyle affect each other. A single, unified dashboard has long been the holy grail for Quantified Selfers, which is why Tictrac ( tictrac.com ), a free Web service, has been getting so much buzz. It not only pulls info from your scale and various activity trackers but can also loop in stats from your email inbox, calendar, social-media accounts and about 50 other data streams. Most important, it lets you compare metrics by dragging and dropping your data, which the website then assembles in beautifully rendered charts and graphs. Does tweeting late at night affect your sleep quality? What effect does your email volume have on your weight? Tictrac makes uncovering trends—and relationships among them—easier and more intuitive than ever.