We can help our mother by:
Depending on your age and abilities, you may not be able to cook a big fancy dinner for your family, but you may be able to whip up a simple lunch for your family.
Ask your mom what she could use help with. She probably has suggestions for things you could do for her.
Keep in mind that you are "helping" the whole family, yourself included. Your mom will appreciate your help but it isn't just her job to keep the household running smoothly; it's the responsibility of each person in the household, right down to very basic chores for the toddlers.
Keep your room clean. Keep track of your things, and put them away when you're done with them. If you do make a mess, clean it up.