Long A (as in "fate") - Say it like the "a" in the word "say".
Long E (as in "beat") - Say it like the "e" in the word "see".
Long I (as in "mile") - Say it like the "i" in the word "pie".
Long O (as in "go") - Say it like the "o" in the word "go".
Long U (as in "cute") - Say it like the "u" in the word "flute".
Remember: The pronunciation of these long vowels can be slightly different depending on the word, but these are good starting points.
Let me know if you'd like more examples or explanation!