Here are some tips on a general Persian accent, the speaker I listened to was from Iran and so, he was a native Farsi speaker but, you know, you get different flavors in Afghanistan or wherever else you look for a general Persian accent. But the oral posture, the tongue is very thick and flat in the mouth, there's not a lot of jaw action. So, you can feel your tongue very think and very heavy in the tongue you're almost already there. If you sigh through the sound you get that oral posture right and you sigh through it, it's like an sound, that's the thinking sound in this general Persian accent where in American English we'd say. In your oral posture for Persian it's.
So, in your Persian accent the T, Th and D sounds become very dentalized, so, that, this, they, dentalized meaning your tongue is right up against your teeth. That, this, they, time, try that. Z sounds become unvoiced to a S sound, so plans in an American English accent would be plain, very short and devoiced at the end. In the same token, V sounds turn into the unvoiced version F sounds, so instead of have you have haf. So, in American English we'd say words like didn't, and hadn't there's nasal plosion so you get some air out of the nose, didn't, hadn't. In your Persian accent it would be didn't, hadn't, no nasal plosion, all the sound comes out the mouth, didn't, hadn't, give that a shot. There's that eh, e, transition, so words like animal, English, become animal, English, English, instead of English, English. And animal, animal, imal, give that a shot.
A lot of ?? sounds, so a lot of two element American English sounds like o, as in goat and own become pure, like goat, own. An own American diphthong as in about and thousand, become about and thousand, a, a, pure sounds, single sounds. Play with a tapped R for your Persian accent, so when you say the word Iran, you can say Iran, and sometimes the accent of that word changes so sometimes it's Iran and sometimes it's Iran, Iran, Iran.
So what's the musicality of this Persian accent, there aren't a lot of unstressed syllables and you hear that in words like animal, animal, and complain, instead of complain, you've got complain, you get a lot of stress on all of the syllables. So, the feeling of the accent is a little bit like this, a little more monotone than a general American accent but don't take my word for it, listen to some native Persian speakers and see what you get from them.