Clef
Treble clef notes
The five lines of the treble clef are E, G, B, D and F, from the bottom up, and the four spaces are F, A, C and E. The treble clef is a stylised letter G. Its curl wraps around the second line and marks it as G, the G just above middle C (G4).
Read it, then play it
Play the note you see on the staff. The exact key counts: how high the note sits tells you which octave.
The lines: E G B D F
From the bottom up, the lines are E, G, B, D and F. The rhyme most people learn is Every Good Boy Does Fine. Each line is a third above the one below it, so you are really skipping every other note name.
The spaces: F A C E
From the bottom up, the spaces are F, A, C and E. The spaces spell a word: FACE.
Read from landmarks, not note by note
Start from the note the clef marks: G on the second line. From there, every line or space up is the next note name and every one down is the note before. Middle C sits on the first ledger line below the staff.
Above and below the staff
Notes that don't fit on the five lines get short ledger lines. With one ledger line either side, the treble clef covers C4 to A5: 13 white keys on the piano.
How to read ledger lines