Decide on a goal

Do you want to run a 5K personal record? Or simply finish your first 50-mile bike ride? A surefire way to stay motivated and hold yourself accountable is to get an event on the calendar. Target a race that’s three to six months away months away so you can budget enough time to train. Try searching active.com or trifind.com for local events.

Follow the 10% rule

If you’re gearing up for a longer distance, the most effective way to increase endurance is by building mileage gradually. Follow the endurance golden rule: Don’t increase mileage by more than 10% per week (e.g., if you’re training for a half marathon and you run 25 miles one week, increase to only 27.5 miles the following week).

Vary your pace

Going one moderate speed for every workout won’t take your endurance to the next level. “Swimming for a straight 30 minutes loses its benefit after doing it five or six times,” says swim coach Gerry Rodrigues of Los Angeles–based aquatics program Tower 26. “You need to incorporate intervals and work different systems.” Try swimming 4×200 yards “descending,” making your last 200 is the fastest. Not only does this build endurance, but also teaches proper pacing so you finish strong.

 Fuel properly

Once you start upping the mileage, you need to treat food as fuel, especially post-workout. Registered sports dietitian Lauren Antonucci of Nutrition Energy in New York City suggests recovering with half a gram of carbs per pound of body weight, and 15 to 20 grams of protein within 30 to 60 minutes after training sessions or races.

Do test sets

Track your progress and push yourself by doing a mini “time trial” every two to three weeks. You could do one mile all out on the treadmill or a 30-minute timed effort on the bike. Keep track of as many stats as you can to chart your progress: pace, heart rate, distance, time and how you feel.

Keep up the strength training

“When done properly, strength training has an excellent carryover to endurance sports,” says physical therapist and triathlon coach Bryan Hill of Rehab United in San Diego. “It will keep you injury-free and ensure that you maintain form all the way to the finish line.” He suggests timed circuits to simulate intervals, high reps with lower weight to aid in muscle endurance, and plyometrics for integrating power.

Schedule recovery days

“Recovery days help prevent injuries and breakdown of your body,” says Adam Friedman, Gold’s Gym Fitness Institute trainer. Treat downtime as part of your training, and schedule at least one recovery day each week.