I like to jog, did a few half-marathons (badly). There are many techniques to improve endurance.

– As has been said, ditch smoking

– Simple carbs before a run, no big meals

– Bring a caffeinated sports gel/candy with you while you run

– Vary your training for incline, surface and length of stride, as it will help your body adapt. When you run, start slowly and gradually pick up speed, then sprint the last half mile

– Breathe deeply and steadily, through the nose while expanding your chest and stomach

– Foot placement is important. Try to land in the middle of the foot and step lightly so you’re not banging joints and tiring out tendons

– Don’t waste energy by jostling too much, swinging your arms, etc. Keep the rest of your body calm and take long, quick steps, low to the ground

– Find an interesting route to keep from being bored, while focusing primarily on the stretch of road in front of you

– Have water handy and take small, frequent sips

– Listen to upbeat music that motivates you, with a steady rhythm

– Light stretching after you’re done, perhaps running cold water over limbs if they’re sore and taking Ibuprofin for inflammation

– Besides caffeine and “Vitamin I,” might want to try supplements like creatine, glutamine, antioxidants, omega-3s, etc

– Wear comfortable, moisture-wicking clothes

– Perhaps most important: get good running shoes. Go to the Running Room or New Balance store and let them test your gait and fit you with something really light and comfortable

Hope this helps!