Tremolo is usually used as an intense effect. Whether a classic surf pulsing or a choppy, almost techno effect, when most people reach for tremolo it’s to create something in your face. But tremolo can also be used for subtle modulation that can add beautiful motion and energy to a track. Try synching a tremolo effect to the tempo of your song, and then applying it to a guitar, bass, or pad track. Use a relatively fast rate (say, eighth or sixteenth notes) but with a low depth.
Used in this way, tremolo can create a sense of movement in an otherwise static track by adding subtle pulsing that you feel more than you hear. Give it a try — you just might find it takes a dull track and adds new life to it!