Present the child with a clean box/basket/bucket of separated pairs of socks.
Provide the child with additional empty baskets, one for each member of the family.
Show the child one sock and ask him to find the other sock that looks the same (i.e. the matching sock).
Fold the socks together (or have your child fold them to work on additional skills such as motor planning and eye-hand coordination) and ask the child to put the pair of socks in the right basket, based on whose socks are they (mom’s, dad’s, child’s, sister’s, etc.).