If your child will be attending first grade in the fall, I would recommend working on the following concepts:
Blending sounds together to make words (ex: b-a-t = bat)
Reading small books with repetition. Small readers can be purchased at Walmart or any bookstore! You can also check out our public library!!!
Counting forward and backward to 50.
Adding/subtracting to 10.
Writing complete sentences using capital letter, noun, verb and correct punctuation.
Stretching out words to hear each sound. This helps your child with both spelling and writing.