nouns, adjectives, participles

Persistent means the stress remains where it is in the base form (i.e. the nominative, the name-form). Does it really? Of course not. It can't. It must obey the general laws of pronunciation. But it only moves towards the back of the word if it is forced to.

Words stressed on ultima

No problem. No problem? A slight change in pronunciation though, short acute becomes long circumflex in genitive and dative.

    ὁ  ἀγρς ἐκ τοῦ  ἀγροῦ
ἐν τῷ ἀγρ
ἐκ τῶν ἀγρν
ἐν τοῖς ἀγροῖς
All other words

If the last syllable is long (but unstressed of course) an acute stress is placed on the syllable before, on the penult. Even if the word was stressed on the antepenult in the nominative, such as ὁ ἄνθρωπος. Or if it had a circumflex on the penult in the nominative, like ὁ δοῦλος for instance. Why? Because that is the easiest way to pronounce those words.

Says who? Said the Greeks!

Try this: νθρωπος. That's fluent and easy.
Now try  ἄνθρωπου with a long UNstressed ου at the end.
It's easy to say ἄνθρωποῦ (2 stresses). But: a word can only have ONE stressed syllable (in normal, everyday speech, even in ancient Greek).
     All right you say. So what about "νθρωπς ἐστιν"? That's got 2 stresses. Yes, but "ἐστιν" doesn't have any, leaning as it does on "man" (see enclitics). So "man" or any other antepenult needs strength and accents for 2.

Now try this: δοῦλος , really long οῦ , short ος . No problem.
So now try: δοῦλῳ dragging out both syllables but stressing only the first. Same as above for  ἀνθρπου, δοῦλῷ (two equal long stresses) would be easy but would make for funny, stilted speech.  δολ sounds much better.

Examples    Remember that plural -oi and -ai are short!
Examples    And here the recording of the following examples:
ὁ τοῦ Φιλππου πατήρ
τὸν Φλιππον καλεῖ
τῷ Φιλππ λέγει
οἱ δολοι
ὁ τῶν δολων βίος
τοῖς δολοις λέγει · ὦ δολοι, ...  
τοὺς δολους καλεῖ
τὸν δολον βλέπει
αἱ Ἀθναι
ἐν ταῖς Ἀθναις
Enough of this. It's up to you now. Read all your Greek out loud till it sounds right.