There is a strong connection between word-reading and spelling development. Students' spelling can provide insight into their word-level reading skills and inform intensive reading interventions delivered within a data-based individualization framework. The purpose of this article is to describe the linguistic knowledge bases that connect word reading and spelling and to provide a step-by-step guide that describes how special educators can use a fine-grained analysis of students' diagnostic spelling assessment data to make adaptations to intensify reading intervention for elementary students with word-level reading disabilities. [This paper was published in "Intervention in School and Clinic" v60 n5 p262-275 2025.]