Song structure & arrangement in Trance/House.

Adding to this as it's still one of the most useful threads on the board. A DJ-friendly skeleton that works for most trance and progressive tracks at around 138 BPM, counted in 8-bar phrases:

1. Intro, 32 bars: kick, bass and hats only, with no big melodic content so the DJ can blend it over the outgoing track. Bring in one new element every 8 or 16 bars.
2. Build, 32 to 48 bars: introduce the main chord or pad sound filtered down, and hint at the hook with a pluck or arp. Keep the full lead back.
3. Breakdown, 32 bars: drop the kick, let the chords and atmosphere breathe, and state the main melody here, often on a softer sound than the drop.
4. Build-up, 16 bars: riser, snare roll and a slow high-pass opening on the music bus. The last bar or half bar of near silence makes the drop land harder.
5. Drop or climax, 32 bars: full lead on top of the breakdown melody, everything back in.
6. Second groove section, 16 to 32 bars: strip back to the groove with small variations so it doesn't feel like a copy of the first half.
7. Outro, 32 bars: mirror the intro, kick and bass only towards the end so the next track can be mixed in.

A few things that help the flow:
- Change something every 8 bars, even if it's tiny: a new hat pattern, a filter move, a crash on the downbeat.
- Mark the start of each phrase with a crash or reverse cymbal so the listener (and the DJ) can hear where the sections fall.
- Keep the intro and outro free of chord changes that clash with other keys. A rhythmic intro mixes into almost anything.
- Lay the arrangement out with coloured blocks before you finish the sound design. Getting the energy curve right early saves a lot of rework later.

For a radio edit, cut the intro and outro to 8 or 16 bars each and shorten the breakdown, but keep the build-up whole, because that's what sells the drop.