There are two ways to run faster:
By increasing your stride length (how far between each step).
Increase cadence (how many steps you take). While stride length will make you faster, it also comes with greater risks of injury. It is useful to be able to increase your stride length at the end of a run for a fast finish but defaulting to extending is risky.
Therefore, to limit injury and run faster, we're going to focus on increasing cadence.
Building your cadence may be difficult at first, but it is worth it.
Nice and simple:
Pick an easy training day, build cadence at easy paces first, and then let that translate into faster efforts.