We’ve all seen suggestions (in textbooks, vel sim.) for how to pronounce Latin vowels. We’re often given pairs of words, and depending on the text the sounds are either un-classical or unlike the sounds of our own dialect of English.
What has worked for many of my students is using disyllabic words or phrases in English, showing the qualities of both the short and long vowel sounds of Latin in that order.
It works as long as you understand that it’s meant to illustrate not the quantity of syllables but the quality of vowels.
As I alluded to in the beginning, you may find that these vowels don’t work in your dialect, but the principle holds: find short, easy, memorable words and phrases that work within the dialect used by your students, and you should see — or rather hear — better results.