Assonance took place between identical stressed vowels of the same length. A 1 syllable word could have assonance with a 2 or more syllable word. Consonance took place between words with corresponding consonants of the same class, final consonants of the same class and quality, and vowels not identical but of the same length. Only the consonants after the stressed vowel count for consonance. The initial consonant in a word only counts toward alliteration.
Alliteration is important.
There must be at least 1 alliterating word per line in the strict meters. Only stressed words count toward alliteration. Alliteration takes place between words beginning with the same consonant or vowel, regardless of length or quality. No non-alliterating stressed word may interrupt the alliterating sequence. Only the root word counts, so nasalizing of words never negates alliteration.