There are a hundred small details I could mention, but here are the more general issues I've found hard: 1, Word order: subject-object-verb, and putting prepositional phrases, adverbials, etc. between the subject and the predicate. 2. Informal vs. Formal Persian: really extreme differences at times! 3. The subjunctive, especially the perfect subjunctive. 4. Obviously the writing takes a long time to get use to, but you do eventually become accustomed to it. To me it seems easy since I went through the horrors of learning Chinese writing :-P But even when you add the harakat short vowels, it's hard to guess when a و is an "o" or an "u". Also, the "hidden tashdid" in Persian is annoying (eg جدی) 5. EZAFE!!!!! On a technical note, typing from right to left sometimes makes my computer go insane, but that's a software issue, not a language one.

Salam Mahdi! Chetori? Well my biggest initial challenge is to learn the alphabet. Unfortunately, the characters available for pc and mobiles as well are too tiny and almost impossible to memorize them. Is there anywhere I can find them in huge letters? Kheily Mamnoon!

Salam, merci man khoobam, to chetori? Here it is: https://freelanguage.org/files/resource/persian-farsi-alphabet-writing-system.png But you'd have bigger challenges later :)