What you'll need - 

- A smartphone or MP3 player

- Earphones to run with

- A metronome app

- Someone to count your baseline number of strides per minute  (ideally!) 

First of all you need to work out a start point - your natural baseline cadence in strides per minute (spm). The easiest way to do this is to get somebody to count for you so that you can run as naturally as possible. Count for 15 seconds and multiply by 4 rather than counting for a whole minute. You can also just count one foot and multiply by two if you find this simpler. A treadmill is the easiest place to do this but can be done outdoors too. 

With this data, work out what a 5% increase from your baseline number is and program this in to the metronome app. 

For example - if you count your natural baseline cadence as 160spm then you will be running at 168spm when increased by 5%.  

Again a treadmill is the best place to start with this as you can make sure that you are running at the same speed but a higher cadence - the biggest and most common mistake that people make at first is increasing their spm by running faster! 

Start with small intervals eg. 30secs with the metronome set at 5% increase, 30secs rest or run with no metronome. This will allow you to get used to the change slowly. Gradually increase the time with the metronome with each run and use this as a warm-up or part of your warm-up protocol before your main session. There is really no need to do longer than 10 minutes with the metronome to make a lasting change. 

During your main sessions try to focus on keeping a high stride rate without following the beep. 

Once the 5% increase feels comfortable then build from there. It's normal at first to feel a bit less efficient when running at the same speed but a higher cadence - don't worry, this will pass and you should end up with better form and eventually be a more efficient, less injury prone runner.