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.
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.
Keep good collection of your favourite songs in your cell phone or mp3 player. Also do not forget to carry your earphone with you.