Sight words are words that the children are learning to read instantly. Gaining a sight word vocabulary is important because these words make up at least half of the words children encounter while learning to read. Also, these are words that writers use most often. It is also important to recognize these words because many of them do not sound as they are spelled, making them difficult to sound out simply by using the rules of phonics. Once the children have mastered the sight words, they are better able to comprehend the story they are reading.
Your child will naturally begin to read sight words simply from seeing them so often. You can help your child to master sight words by pointing them out, reviewing them by making flash cards, "labeling" your home, etc.