An appallingly tardy response to such an important element of reading - apologies. The growing recognition of fluency as the crucial developmental area for primary education is certainly encouraging helping us move away from the obsession with reading comprehension tests.

It is, as you suggest, a nuanced pedagogy with the tripartite algorithm of rate, accuracy and prosody at times conflating the landscape and often leading to an educational shrug of the shoulders, a convenient abdication of responsibility and a return to comprehension 'skills'.

Taking each element separately (but not hierarchically) may be helpful but always remembering that for fluency they occur simultaneously (not dissimilar to sentence structure, text structure and rhetoric in fluent writing).

Rate, or words-read-per-minute, is the easiest. Faster reading speeds are EVIDENCE of fluency development but attempting to 'teach' children(or anyone) to read faster is fallacious (Carver, 1985) and will result in processing deficit which in young readers will be catastrophic.

Reading rate is dependent upon eye-movements and cognitive processing development along with orthographic development (more on this later).