Well, it's real simple.

If two words rhyme with "perfect" rhyme, the last accented vowel sound and all sounds after that are identical.

Example: Hit....Fit....Sit....lit.....


In assonace, just the vowel sound is important. The following consonant sounds don't have to be the same as in perfect rhyme.


Example: Trip, Fish, List, Rim....the short "i" sound


ugh...just play around with it