Teach your second-grader persistence. Sticking with a subject or activity for as long as it takes to master it is important to success. Once the child masters a difficult subject after persisting, he will feel a sense of accomplishment and self-satisfaction that will motivate him to apply the same persistence the next time a difficult task comes along. This encourages intrinsic motivation, which helps your child retain the information he just learned.
Challenge your second-grader with appropriate learning challenges. When a child faces a difficult task and succeeds in working through the challenge, he experiences self-satisfaction that makes him want to take on a more difficult challenge. In addition to promoting intrinsic motivation, your child is also retaining the information he used during the first challenge to succeed in the next challenge, which will help him remember the information longer and more accurately.
Refrain from allowing your child to become too dependent on you. If your child requires you to entertain him and help him with everything, you are hindering his ability to retain information. Rather than allowing him to become too dependent, provide him with toys, activities and games that promote independence. A child that can entertain himself with his imagination is more capable of retaining information he might find useful when playing games.
Encourage your child to read; children that read often have a higher vocabulary and better spelling skills than children who do not read.