Its kinda funny, in a sad sort of way, but most folks just figure they already know how to run without any preparation or thought. Same with walking, which you should get down first before you even try running.
Since the OP didn't bother with any advice to follow the thread title I will throw a bit out here.
Walk first. Point both sets of your toes straight out in front of you as you walk. Keep them straight. I know that you already figure they are, but they are not.
How do I know? Because I watch how people walk. I can tell whether you are right or left handed by the way your walk is wrong. Right handed people walk right duck footed, left handed people walk left duck footed. Usually, right handed folks persistently walk with their left toes pointed out straight in front of them in good form and their right foot cantered out to the right like a duck. The opposite is true for lefties. Don't believe me? Just sit and watch a bunch of people walk by, see which direction their toes point as they walk. You will learn.If your walk is not in line, you will stress all of your leg and hip joins, they will hurt a bunch and you will stop. Pay attention to this.
OK, now you are watching that your toes always point forward as you walk. Now, make sure that when you put your foot down it goes heel to toe every time. Not flat, not hard on the heel, not on the ball - heel to toe every step, with a rolling motion. Keep it smooth and regular. Start as slow as you must, pick up speed as you can.
After you have mastered walking and bumped up your speed to your personal maximum, then you can start to run. Just run for 50 - 100 feet at a time first, then go back to walking. After you are comfortable with this, extend the time running and cut the time walking. Same drill: toes pointed straight out in front of you, roll each step heel to toe. As you go further, make a point to focus your eyes at the horizon or where it should be if there is stuff in the way when you run. That will keep you from crouching over as you run putting stress on your lower back.
OK, there are some pointers to get you going, in case you don't want to go out looking for them. These are the pivotal ones too, the rest is less important. If you stick to it you will reap the benefits, if you quit than you won't.
One last tip: use good shoes. Every 6 months I buy 3 new pairs of running shoes and I retire the old sets. I use Aesics running shoes, but there are other good brands. If you are serious about running, go to a running store to get your shoes, make sure they fit and use one of those fancy readers you stand on to find where you put your weight before you buy them. Any good running store will have one.
O.K. I will add to this for the man knows what he is saying . The kick is important too. Be aware of what your leg is doing behind you when your leg is lifted . Keep it straight behind you just like you do your toes hitting the ground in front of you . Yeah you do , you wing them out side to side . Keep them straight behind you. You will feel the difference when you do .
There is much debate on whether your hands and arms are at your side or at your buttock as you swing your arms . I personally keep mine at my side , but that was the way I was taught . Some of the newer runners keep them down by there buttock and have had lots of success in winning races . The theory is you get more pendulum effect and can conserve energy better with them hanging lower. I think it is more personal choice my self. The main thing is to pace your self