This summer some parents at the beach asked me what they could do to get their pre-K and K aged children ready for school. I had some simple, but very important answers for them: experiential learning, vocabulary development, and a positive feeling about school. Many parents worry about their children being able to count, write, and read before they get into school. That's fine and dandy, and very helpful, but if they don't have the words and experiences to read and write about, it's useless.
fantasy and reality.
Get children to use their senses. You'd be surprised at how few students can describe how objects physically feel. Quick investigation: Ask a child how something feels or tastes. 50% of the time you'll get the answers, "good" or "bad." Watching something on tv or on a computer screen is not the same thing as experiencing it in real life. We do rubbings in school to help us describe textures. It helps students who have sensory issues to cope with the sensations and it helps all students with descriptive writing and science inquiry.
Pack a special lunch with a note! Remember that young children don't have a good concept about time until about second grade. Most primary grade teachers post a visual schedule for students to know what to expect. Give them clues about when school will be over. (Two "Backyardigans" until gym then one "Blues Clues" until snack.) And NEVER use school, writing, or "Your teacher is going to be mad" as a threat!