Dirhams are useful in cash for tips, toilets, and stalls. Cards work in many riads. We will never ask you to handle the tour balance in a medina alley.
Dress for respect and sun: shoulders and knees covered in rural areas and medinas is a comfortable default, not a law for tourists. In camp, wear what the temperature demands.
Tipping drivers and camp staff is customary; we can suggest ranges without making it awkward. Entrance fees are usually extra so you only enter what you want.
Distances: Marrakech to Merzouga is not a morning. Anyone who sells it as such is selling a different country. Read the day-by-day on our 3-day desert tour and believe the hours.
The best tip is the one we started with: travel privately, say what you need, and let the itinerary move.
Further reading from an official source: official Visit Morocco tourism website (Visit Morocco — Moroccan National Tourist Office).