Don't rush out and buy educational products right away. The first step is to engage your child's attitude toward learning. This begins in the cradle. Some theorists would argue that it begins in the womb.
From the time you bring your infant home from the hospital, you can play music. Speak to your child. Show her books and stories. Talk about colors. Don't talk baby-talk. Vary the pitch of your voice. Stimulate the senses. Discuss the foods your feed your child. "These are bananas. See how yellow they are? I mash them up. Do you like them?" You may feel silly at first. But a child's brain develops rapidly in the early years.
When he is old enough to draw or color, don't rush him to write the alphabet. Work on sound-letter correspondance. Plastic letters are helpful at this point. Until a child understands that each letter stands for a sound, there is no reason to make a child write her name, or CAT, or anything. On the other hand, you can begin to introduce phonetic awareness. "Hear the sound at the beginning of Peanut butter? That's a 'P.' See it on the jar? What else starts with the 'p' sound?" Then he is ready to write and spell.
Similarly, with numbers, there is more value in teaching a kid to count and sort than in reciting, "2X2=4."
A kid can sort Easter eggs or plastic figures--or socks. They can group plastic containers according to size. They can see that each container has a lid. How many lids are left over? Which is bigger? Which is biggest? Use terms of comparison. An older preschooler can sort beans. Using muffin cups, they can put 6 beans of each color into a section of the muffin pan. These activities prepare a child in verbal skills and math skills.
Too often, we launch kids into a regime of video games and cartoons in order to keep them busy, quiet, and out of our hair. A steady mental diet of books and basic playthings is much more stimulating. If the child is a passive observer all the time, she'll be less likely to develop curiosity and wonder about the world around her. If you speak to your child and encourage constant thinking and evaluating, you'll set her up to learn.
Learning takes place on many levels. While we're instructing the intellect, we're also helping to develop a moral code. We're establishing a sense of self, an enjoyment of beauty, a listening ear for music. Parents are the first and most important teachers.
If you have the resources, many great products enhance reading readiness and math thinking. If not, don't worry. You already have in your home most things necessary for getting your kid ready for school. The most crucial is, perhaps, a sense of your own responsibility.