Body position and posture is one key to proper and healthy running form. You want to have your body weight directly over your feet when they hit the ground and your hips and head aligned as well.
Below is how SKORA Running shoes describe the proper form:
The position of your body greatly affects your running form.
Maintain an upright posture, alinging the hip to head. Land with your feet under your body, not in front. Keep your knees slightly bent, avoid landing with an outstretched, straight leg.
A good running body position enables the legs and feet to naturally absorb impact energy and forces throughout the body. Read more here.
Reading about it and then doing it is sometimes difficult, especially when you can’t see yourself from the side to see if you are properly aligned. Here is how I put myself in a comfortable running posture that promotes good form:
Chest out – this gets me slightly forward with my forward weight, but not enough to throw off my balance.
Elbows back – pulling your elbows back helps to relax your shoulders and align your head with your hips.
Hands at nipples – having your hands relaxed and brining them up around the height of your chest helps to keep your shoulders relaxed. My running coach wrote an article about arm position recently. Check it out.
Now roar like a T-Rex – since you kind of look like one. A fast T-Rex.
Those three (you can skip the roar) points make me focus and remind me to keep my form in check, even when I am fatigued.