When your destination is about to arrive, just be ready with your bags and count all the items. Most of the people do this mistake and they often miss their belongings in the bus.
Make a checklist in advance for all the items which you would be carrying during the bus journey. Check this list prior to leaving your home to make sure that you have not missed any item.
Pack as light as you can and try to avoid taking unnecessary items with you which will make your journey uncomfortable and tiring.