1. Pace yourself. Intervals train you to run a goal race pace, whether it's a six-minute-mile pace or a 10-minute-mile pace. During your interval sessions, you want to run slightly faster than this pace so come race time, your goal pace will feel comfortable.
2. Pick the right distance. If you're training for a 5K, start with quarter-mile repeats, then move up to half-miles and then miles. For 10K or half-marathon training, you'll need to do longer intervals. Start with half-miles and build up to mile and two-mile repeats. Ever so often, swap your interval training for 5- or 10K races.
3. Keep it short. Your total speedwork distance should never add up to more than 10 to 15 percent of your weekly mileage.
4. Gradually reduce your recoveries. When starting out, allow yourself to recover for half the amount of time it takes you to run the interval. Gradually shorten your recovery to simulate your goal race.
5. Taper. If you have a race in a few days, keep your speedwork short and sweet. Run short intervals of 100 to 400 meters at race pace.
6. Mix it up. Running the same distance over and over is boring. Instead, pick different distances to run that are appropriate to your goal race.
7. Give yourself a break. Schedule your speed session at least three to four days after your long run to allow optimal muscle recovery.