Exercise 1 - Write the diacritics you hear: huyền, nặng, sắc, ngã, hỏi, nặng, hỏi, sắc, ngã
Exercise 2 - Listen and write down the vowels and their accents:
ô, ô, ồ, ổ, ỗ, ố, ộ, ồ
ơ, ớ, ở, ợ, ờ, ỡ
ề, ê, ể, ế, ễ, ệ , ê

Steps to pronounce a Vietnamese word.
E.g. CHÀO
First pronounce the vowel separately then their combination if any. A-O-AO
Second, pronounce the consonant or consonant clusters. CH
Third, repeat the vowel or vowel combination then articulate both together. AO-CHAO
Fourth, add the accent if any. HUYỀN
Last, after you add the accent, you need the say the whole word with the accent. CHÀO.