Babysitting two small children?

so im 16 now, responsible and mature for my age, i have babysat before and took the course when i was 11 tomorrow im babysitting a family members children one girl late 2's early 3's and a brother about a year younger from the christmas partys and other get togethers that they have attended they dont seem to be incredibly naughty the boy is more quiet and the girl is more difficult but anyways can someone give me a refresher as to things to do how to entertain them and things i need to know for all small children that i may have forgotten its not that im mindless and remember nothing i just want some help to make sure things go as smoothly as anything including small children can be lol