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.
Before you start the journey, always check the route and make sure its safe to travel from that route specially if you are planning to travel during night.
Get cell number of the bus conductor. In case you miss something in the bus then you can reach the conductor and ask him to keep your belonging with him.