To get a perfect pelt, first, you need to study your prey, once studied, beside its name it'll show the quality of the prey, while looking at the prey, press R1 or RB to show info so that it will show what type of weapon and ammo to use to kill it with one shot preferably on the head or if you have a more leveled up dead eye, any highligted weakness it shows, I suggest you use a binocular from far away to study it, and don't forget to kill it with one shot otherwise the quality will degrade.
I never get the option to study my prey, I guess I'm out of range with my long scope sniper rifle. When I get closer they usually spook. Yet I don't use cover scent or pay attention to the wind, clear shot from far away usually does the trick.
The glitches never end. I was hunting again and somehow I had lost all my ammo for the Varmint rifle, 0. I had bought the max amount, shot it 3 times and empty grrr. Then I almost lost my perfect boar pelt in a wolf attack. My horse uselessly threw me off again with no useful weapons to use so I went beserk on them and punched them all out one by one. Bring it own you crap wolves, fist fight to the death, works much better than a revolver. Pelt saved.
The crap AI never seizes to amaze as well. At the end of a mission I had to flee the police in the harbor. So I try to hide under a dock. Nope, AI can see through everything. After a mad dash I jumped in a row boat and casually rowed off. They had no answer to that... I have no clue why they were after me in the first place, just got a $10 bounty at the end of the mission to get me to clear out I guess.
Ok, back to the gun smith to rebuy ammo for the varmint gun. So far only 1 poor rabbit pelt. Either an arrow doesn't work or it was just a crap rabbit. My horse has trampled a dozen over the course of the game yet that doesn't yield any good pelts either :)
Sorry for the late reply, haven't frequent the forums like this since BotW and TW3, just so you know, you can still study any animals with or without the binoculars or scope, you just have to get near enough to get a focus on your prey, and seems like you're having a hard time getting near one as well, when you're in eagle vision(L3+R3) an odor can be seen on your person, that way you can tell the direction of the wind and help you to keep your scent off the prey so they don't get spooked, now knowing this you can easily study a prey with or without the scope or binoculars and hunt accordingly once you studied the prey, it's really easy once you get used to it, be patient my man.