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.
In case you want to take a longer break at some bus stop due to natures call then inform the bus conductor about the delay so that he will wait for you.
In case your family members have not got adjacent seats during automatic seat assignment then make a humble request to other travellers and try for seat exchange so that all of you can sit together.