A simple exercise for keyboard is today's post. It's a great technique that works really well with a pad on keyboard - like a strings or synth pad. The animation below is a little fast but it works fine for educational purposes. Considering the variety of tempos, styles and sounds available all that the animation really needs to show is the concept.
When you are playing a cool pad sound behind some chords (or even without any chords at all, maybe just some drums and bass) use this technique to add a little tonal shift to the sound. Simply release the fifth note of your chords whilst holding down your root and third notes. Practice a little and start working this into your own playing style. Experiment with how long you hold the 5th before letting it vanish.