Create a schedule for yourself: There's no reason you can't learn to compose like Bach or Chopin--their ability is primarily the result of practice and dedication. Write down a timetable that dedicates at least an hour a day, five days a week to your practice, and be diligent and stick to it. Certainly this rigidity and drive are the most essential elements to building a foundation for the study of this classic and difficult instrument.
Sit down at your synthesizer, piano or keyboard and get ready to become familiar with the notes. Play the white keys, which represent whole notes; by sticking to them you will remain in the key of C. This key has no sharps or flat notes.
Look anywhere on your keyboard for two consecutive white notes. These notes are either E followed by F or B followed by C. It's easy to find out which keys you are playing.
Start moving up the white keys, counting as you play each note. If it takes four steps to reach the next pair of adjacent white keys, you started on a B. This progression is B-C-D-E. E is followed by F with no black key between them.
If it took you five steps, you began on an E and ended on B. The progression is E-F-G-A-B.
The black keys you just skipped are the sharp or flat notes. They are called sharp or flat depending on the key the music is played in.
Play one entire octave of notes (from one C to the next). This time play every note. You play C, D flat, D, E flat, E, F, G flat, G, A flat, A, B flat, B and C.
Sharp notes work exactly the same way, but based on the note played previously. Start at the same C. You play C, C sharp, D, D sharp, E, F, F sharp, G, G sharp, A, A sharp, B and C.
The notes played are the same, the only difference being the reference note. Label the notes on your keyboard by taping on each key the name of the note.
Pick up your book of piano notation and examine the clef on the top-most line. This is called the G clef and it designates where on the music notation the G note lies. Count from the lowest line of the G clef, learning where other notes rest.
The lowest line is E, the space thereafter F, the second line is G, followed by A in space, B on a line, C in space, D on a line, E in the last space, and F on the last line. For notes appearing above or below the lined portion of notation, count from the nearest reference point you know.
The F clef works in the exact same way, indicating the F line by surrounding it on either side with periods.
It can help to make up a phrase for remembering the notation lines. G's phrase might be: Every French Girl Ate Brunch Calmly During Each Film.
F's phrase: Good Apples Bring Crunchy Dinner Even For Gigantic Ants.
Make up your own and make sure it helps you accurately identify every line.
Memorize the circle of fifths; this is the only way to know what notes in your song should be sharp or flat. Pick a key and look up which notes therein are sharp or flat. Begin to write a melody by playing different arrangements of the notes in the key of your choosing.
Keep in mind that most popular music relies heavily on the root note, or namesake of the key, the third, fifth and seventh notes.
Play C (1st) E (3rd) G (5th) and B (7th).
Set your metronome for any steady B.P.M. (beats per minute) and play a melody in your key, trying to stay in time with the metronome. Thirty would be slow, 60 moderate and 90 fast.
There are no rigid guidelines when writing a melody; experiment and find a progression of notes you enjoy, then begin working them into a song.
Congratulations, you have composed your first piece.