3. Go shopping
Sit together and decide whom your kids would like to present gifts and make lists for every kid. When you have too many relatives (cousins, nephews, and other siblings) divide them all between your kids, so that each would give a present from the whole family. After this is decided, get down to the financial side of the problem. Make sure your kids get an equal amount of money for presents.
More likely you will go to 1$ shop so take that into consideration when deciding budget. When you are there let the kids choose best presents to their mind. When a present is chosen put a tick near the corresponding name. Thus you won`t forget anybody and leave without attention.