Right now I am working a lot with teaching LoLo (age 4) his sight words. I start by teaching the words through chants, for example: T-H-E spells the, T-H-E spells the, high-ho the dairy-oh T-H-E spells the.
As we sing this chant, we often have an index card in front of us with the word written on it. I point to the letters as we chant, then we look for the word everywhere.
When I read stories at night, I have LoLo point to all the words the on the page. Or sometimes I will stop reading and ask him what the word is. I show him examples in my books, magazines, and mail. He gets really excited that he can recognize this word so quickly all over the place. I make sure that as we learn new sight words that we always review the previous ones.
Quick Fact: Here in the state of California, kindergarten students should be able to recognize (and at some schools spell) the top 100 sight words! That is quite a task for a 6 year old.