Push Your Chest Out
One of the major mistakes a beginner level jogger commits is that while jogging, they kinda slouch. This is a pretty incorrect posture in an exercise such as jogging. There are two major things slouching affects - one, your posture and secondly, the health of your spine.
I see a lot of people jogging, their heads down and in a very casual flabby state. Normally, jogging should mean serious business for you if you plan to gain the benefits it brings to the forefront.
You should jog with your face front, head high and your chest out. Jogging brings about a lot of benefits to those that engage in the exercise."
Be it on the road side, the streets in your area or even the one in your house (aka treadmill), the right posture for jogging is to push your chest out. Then, your shoulders should also be rolled back.
With the right posture for jogging, you save yourself the risk of falling into spine related injuries. You equally build and maintain the right posture in the long run.