Use sight words on the typical rectangular post cards. But instead of using the rectangular ones, clip off the sides and make them round. This will eliminate needless space and will highlight the word on the card to help the child focus on the word.
Visit different websites. Online, you'll find sites that provide a list of words for parents to work with (see Resources below). Also, talk with the teacher and see if they have a list of sight words.
Prioritize the list of sight words. Avoid giving the child sight word overload. Throwing a long list of words at a child will only work against both them and you. Focus on 5 to 8 words at a time and do not move on until the child has mastered the words.
Seek out the child's learning mode. Some kids learn by feeling, hearing, seeing and touching. Normally a child can learn using a multiple array of these modes, but knowing which method works best for a child is important. Let them hold the card, say the word out loud and show them the word on the card. Observe which method the child responds to best and focus on that mode.
Spend lots of time practicing the words. It only takes a few minutes to practice a handful of sight words, but the reward lasts a lifetime. Take 5 to 10 minutes every day and practice, practice, practice.