1–2: counting nights as days and ignoring the gateway
Write arrival and departure times beside each destination. Then include transport to and from the gateway. Three nights do not necessarily give you three full days of exploring.
3–4: comparing headline prices and overfilling the route
Use complete costs, including transfers, meals and required fees. Choose a few priorities rather than treating every named island as essential. Each move brings packing, waiting and another connection.
5: using one season label for a whole country
Check the island group and activity, especially when comparing places as far apart as Bali and Raja Ampat. A monthly average is not a forecast for your departure.
6: assuming every boat includes the same service
Check the itinerary, guiding, equipment, landing arrangements and weather policy. Distinguish a transport ticket from an activity programme and a private booking.
7: leaving the return until last
Secure the return arrangement and understand the consequences of a delay. Keep a buffer before important onward travel. Put the return details in the same plan as the outward journey so they are easy to find.