Three common mistakes that you should be aware of while you are running, are where you're swinging your arms, what your hips are doing while you are running and how your posture is. Now I'll show you what I'm talking about. When you are swinging your arms you want your elbows about at ninety degree angle and you wanna relax your hands. But where you are swinging your arms try to keep them from going across your midline. What you just might see when you are watching people is having them swinging their hands across their chest. This will throw off your balance a little bit. And with your hips, try to be aware of what your hips are doing while you are running. If you notice while you are running, are you letting your hips tip a little bit, or you are keeping them stable and are you keeping them in a forward motion? Are they tipped forward or are they tipped under? Try to tuck your hips just a little bit but just enough so you are moving in a forward direction. As you are running try to notice what your posture is doing. Are you getting tired? Are your shoulders creeping up towards your ears? And are you holding tension here? Are you leaning forward? Engage your core, keep your torso up, keep your airway open and try to relax while you are running. But try to also pay attention to what your form is doing. So again notice what your arms are doing. Keep your arms relaxed. Keep them from going across that midline. Pay attention to your hips. Stabilize your hips, keep them forward. And watch what your posture is doing. Try to engage a little bit, but relax at the same time and keep your chest up and open so that you have a better and more comfortable run.