Summarize this article:

You want to run with the same poise that you walk. Don't hunch or bend your back as you run, keep your spine as straight as possible. Plantar flexion occurs when you push off the ground by flexing your ankle joint. Dorsiflexion is the process of pulling your knee up off of the ground at a 90-degree angle. This reloads your ankle for forward push-off. As you run, alternate driving your elbows back and forward in an exaggerated motion. As your elbow drives back, your opposite knee should lift up. Your elbows should also be bent at about 90-degree angles. The longer your stride, the more effective your forward motions will be. To create longer strides, use your legs to push rather than pull you forward. This means the bulk of the power when you run should come from whichever leg is behind during the push-off. Once you have the basic technique down, you can begin to decrease the interval between each stride, meaning you will pick up the pace and run faster. Try not to compromise your stride length as you increase your speed. To develop speed over long distances, first incorporate intervals of 30-second or one-minute sprints into your runs.

Summary:
Pay attention to your posture. Practice your plantar flexion and dorsiflexion. Use your arms to propel you forward. Lengthen your stride. Increase your stride frequency. Begin to incorporate short bursts of speed training into your longer runs.