Note: there is now an even more musical method available in Denemo version 2.6!
This video shows how you can enter music notation using the Denemo score writer quickly and musically.
In this example a well known tune is entered and beautifully typeset in under 40 seconds.
You play the rhythm first and then play the notes. Both of these activities are like drumming or playing the music, rather than technical note by note entering of data.
Denemo is a free and open source music editor (denemo.org) which you adjust to suit your own purposes. It uses the world-class LilyPond music engraver to give scores that are a delight to play from, without you having to tweak the placement of the notation.