Breathing properly is probably more important than you think. It will help you run longer, faster and more efficient without getting so tired. First of all, you need to have a straight posture with your shoulders leaning slightly backward. This will open your lungs so more oxygen can enter your lungs. A great way to practice this is to always look forward and try to point your chest in a 30* angel upwards. Your posture is essential.
Second of all, breathe in throw your nouse and out throw your nouse. Breathing in throw your mouth and out throw your mouth, can make your mouth dry and you don’t want to dehydrate while your running. Another thing is that your brain concentrates better if you breathe in to your nose and out throw your nose weirdly enough.
The last factor of them all is where you breathe. Sounds weird, but what I mean is that your belly should raise not your chest. If you breathe with your belly moving it’s good. But if your not, does just mean that you don’t allow as much oxygen to enter your lungs and you need to practice these breathing technics.
Summary: Straight posture, chest pointing upwards, breathe in trow your nouse and out throw your nouse and your belly should move not your chest. So on your next run keep these things in mind and enjoy