Expert level: Songwriting
Use copy and paste
Whether recording guitars or tapping out keyboard lines, use GarageBand’s ‘Tracks’ view on iOS/the tracks area on macOS to copy and paste from your best performances or cover up errors.
Don’t imagine pros avoid this – plenty of songs that sound ‘live’ in fact use individual notes taken from dozens of performances.
If you record a MIDI instrument (such as a synth, drum machine, or Smart Instrument), individual notes can be adjusted by moving or resizing them on the piano roll.
On iOS, enter Tracks view, tap an audio region and select Edit from the menu.
Arrange your song
Use GarageBand’s ‘arrange tools’ to create song sections (verse, chorus, and so on) that can be copy/pasted/reordered in their entirety.
On macOS, Track > Show Arrangement Track makes the feature visible. On iOS, ‘Song Sections’ are more limited (no section naming), and accessed via the + menu in Tracks view.
If you have lots of tracks, you might find your song becomes muddied. Use GarageBand’s track header tools to adjust the volume and panning of individual tracks, to boost clarity.
You can also mute and solo tracks, respectively, to temporarily disable some and focus on a few specific parts.