Write a melody using pitches that sound high. The treble clef is where you will place these high notes. When writing the melody, you want to avoid using too much harmony and just write one single melodic line.
Write some chords in the bass clef. Chords consist of three notes that are each spaced three pitches apart. Think about chord progressions that work well with your melody. Place a heavy emphasis on the tonic chord and use the dominant chord in order to create a sense of finality in your music.
Break the chords up into arpeggios. To do this, instead of having all three notes of a chord play at once, have them play one after another in succession. This will make the music more interesting and provide you with a better texture for the piece.
Write chords that are within the reach of an average pianist, which is just over an octave. The distance from one musical letter name to the next is an octave. For instance, C to the next C ascending would be one octave. Some pianists can reach much further and some have to use a special technique to play chords that span over the octave.
Place piano rolls in the music to give the chords more definition and provide shimmer to the piece. Piano rolls are when you have the pianist play the notes from the bottom to the top in quick succession. This is different from playing a chord, in which you play all notes simultaneously.
Create piano pedal markings to indicate how the pianist should pedal the piece. The damper pedal on the right of the piano will create a wash of sound and sustain any pitches that you play. The sostenuto pedal on the left of the piano will only sustain the notes that were held down immediately before depressing the pedal.