One great way to increase reading fluency is to build word reading fluency skills. The Dolch Reading list, for preschoolers through grade three, includes many of the most commonly used English words in books for children. Many of them are considered
sight words because they are difficult or impossible to sound out. Story reading fluency increases when children are able to read these words more quickly and fluently. You can find a list of the Dolch Words in this article:
Dolch Word Lists - Reading