Using Greek at a research level requires a better understanding of Greek accents. Dan Wallace recommended D.A. Carson’s Greek Accents: A Students Manual. I also found this Accentuation Tutorial pretty helpful.
Here are some of the important aspects that I’ve abstracted from these sources:
1. Apart from exceptions, every Greek word must have an accent, but only one accent.
2. An acute accent may stand only on an ultima, a penult, or an antepenult; a circumflex accent may stand only on an ultima or a penult; and a grave accent may stand only on an ultima.
3. The circumflex accent cannot stand on a short syllable.
4. If the ultima is long, then:
a. the antepenult cannot have any accent, and
b. the penult, if it is accented at all, must have the acute.
5. If the ultima is short, then a long penult, if it is accented at all, must have the circumflex accent.
6. An acute accent on the ultima of a word is changed to a grave when followed, without intervening mark of punctuation, by another word or words.
1. The accent is finite verbal forms is recessive.
2. In contract verbs, if either of the contracting syllables, before contraction, has an accent, then the resulting contracted syllable has an accent
a. If the resulting contracted syllable is a penult or an antepenult, and has an accent, the GR always tell what kind of accent it will be.
b. If the resulting contracted syllable is an ultima, and has an accent, the accent must be a circumflex.
In nouns, the accent remains on the same syllable as in the nominative singular, as nearly as the GR and exceptions will permit.
Enclitics and Proclitics
The word before an enclitic does not change an acute accent on the ultima to the grave.