Print a list of Latin nouns and their meanings. One of the easiest way to learn from such a list is to create flashcards with the English words on one side and the Latin words on the other. You could also put the English words in one column and the Latin words in another. If you use an excel spreadsheet you can re-sort the columns and make a worksheet where students draw a line from the latin word to its corresponding English word.
Find a list of Latin verbs and print them as well. You can use the same method of memorization with the verbs that you used with the nouns, like flashcards and comparative lists. See which words are similar to their English counterparts. Which words are different?
Adding an -us ending to a Latin verb puts it into the active plural tense, for example. The root verb for love is amo, and when we (more than one of us, so plural) are currently (actively) loving, it's amus, pronounced "a moose" but for magic spell writing purposes, and to take advantage of the Harry Potter British accent you can choose to allow students to say "us" instead.
For Magic Spell-writing sake, add an -us ending to the nouns, so that all of the words can rhyme. Make sure students know that the real Latin nouns and verbs all change ending according to how they are used, Latin is a language of few words with many meanings. The meanings of the words change according to their suffix.