Some children work their way through the reading levels with their peers but their spelling seems to lag behind, others struggle with reading and spelling from Kindergarten. Some students are functional readers, who do fine on their weekly spelling tests, but their creative writing is full of spelling errors and the speed or accuracy of their reading and writing may prevent them performing in tests and exams. Some researchers call this more hidden impairment "stealth dyslexia". All these children exert far more than the typical effort to complete reading and writing tasks, and far from being 'lazy' spellers, they are doing very well to keep up considering they are missing some of the basic skills normally developed along the path to fluent literacy.
So, what does good spelling instruction involve? Phonology, morphology and orthography are basics.
Phonological awareness is well established as a basic for reading instruction, but is also essential for spelling. It involves recognising the sounds and syllables in the word and sequencing them correctly for different words.
Morphology is often taught after reading and writing skills are established, but recent research shows that it is of benefit as early as Kindergarten to reading instruction, and it is also essential for spelling. It involves recognising the parts of words that change the meaning of a word. For example, the 's' on the end of "cats" means there must be more than one cat.
Orthography is the letters we use to represent the sounds of our language. English has a complex orthography, that is, many different ways to write a single sound, and often more than one sound for a particular letter. However, the majority of our orthography does follow predictable patterns or 'spelling rules' and parts that don't fit often become more logical once you know whether the word or part of the word came from Latin, Greek or Anglo-Saxon origins.
If your child is using 'read, cover, write, check', to memorise words for their weekly spelling test, but doesn't use phonology (the sounding out), morphology (the units of meaning in the word), and orthography (spelling 'rules') to inform their spelling choices, then they are probably getting letters in the wrong order or missing letters. These errors are affecting their reading too.
If your child is receiving good spelling instruction but still struggling with spelling and therefore reading too, there is probably an underlying difficulty that will benefit from specialist assessment. A good place to start is with a speech pathology assessment.