What is the best way to help a child become a strong reader? Read to them.
More specifically, have fun reading to them, regularly.
When my son was a baby, I started a daily habit of reading to him for just as long as he was interested. By the time he was two-and-a-half, I had to cut back to just an hour or so a day!
My children's "big cousins" are avid readers and great students in late elementary and middle school. My sister-in-law told me that when they went through stages of being uninterested, she would read to them while they played. I think that's a great tip.
Some of our favorite board books.