Ukrainian is written in Cyrillic, and if you already associate that script with Russian, the first thing worth unlearning is that the two alphabets are the same. They overlap heavily, because both descend from the same medieval writing system, but Ukrainian keeps letters Russian dropped long ago, drops a few Russian keeps, and gives one very common letter a sound Russian gives to a different letter entirely. Reading Ukrainian well means learning where the two scripts quietly disagree, not memorising a Cyrillic chart labelled "Slavic" and assuming it was made with Ukrainian in mind.
The letters that lie about their shape
The first trap has nothing to do with Ukrainian specifically — it is the trap of any Cyrillic alphabet, for anyone used to reading Latin letters. Several Ukrainian letters are drawn exactly like Latin ones and stand for something else entirely. в (v) looks like a Latin "b" but is pronounced "v". р (r) looks like a Latin "p" but is a rolled "r". с (s) looks like a Latin "c" but is an "s". н (n) looks like a Latin "h" but is an "n". у (u) looks like a Latin "y" but is an "oo" sound. None of this is difficult once you know it, but it is exactly the kind of thing that quietly slows reading for weeks if nobody points it out, because your eye keeps offering the wrong sound before your memory can correct it.
The letters Russian does not have
The second trap runs the other way: letters that exist in Ukrainian and not in the Russian alphabet, which matters whenever the material in front of you was written for Russian and only relabelled. і (i) is a plain "ee" sound, and Ukrainian uses it constantly in places where Russian uses a different letter for a duller vowel. ї (yi) adds a "y" glide in front of that same sound. є (ye) is a "ye" sound. And ґ (g) marks a hard "g", the sound at the start of "go" — a letter Russian does not need, because in Russian the plain letter г already makes that sound.
That last one is worth sitting with, because it points at something bigger than one missing letter. In Ukrainian, plain г (h) is not a hard "g" at all — it is closer to an English "h". Друг (druh), "friend", ends on a breathy "h", not the hard "g" that a Russian-trained ear would put there. Ukrainian keeps ґ specifically for the handful of words that do need a true "g", which frees plain г to be an "h" everywhere else. Get this one backwards and it is not a small accent slip — it is pronouncing Ukrainian with Russian's sound system, which is worth avoiding from the first week rather than unlearning later.
Why "Slavic" is not a language
This is the practical warning behind the alphabet lesson. Cyrillic charts, phrase sheets and even flashcard decks are often built for Russian and passed off as covering "Slavic" languages in general, or Ukrainian specifically, without anyone having checked the letters against it. A chart that leaves out і, ї, є and ґ, or that teaches plain г as a hard "g", was built for Russian, whatever the label on it says. It is worth checking any new resource against those four letters before trusting it with your pronunciation.
Learning it now rather than earlier
One thing has genuinely changed for anyone starting Ukrainian in the last few years: the community around it is unusually active. Interest in the language has grown for reasons that need no explanation here, and a noticeable number of people teaching, translating and building learner-facing material for Ukrainian are doing it now, from scratch, rather than adapting something written decades ago for a different audience. That does not replace checking your sources, but it does mean the newest material you find is more likely to have been made with Ukrainian specifically in mind, by people who care whether г and ґ stay apart.
Watch Your Language shows every Ukrainian word in Cyrillic
with its romanisation next to it, so кіт (kit) is never a word
you have to sound out alone. It puts a handful of words at a time on your
iPhone Lock Screen and Apple Watch face, which is a reasonable place to
build the habit of reading Cyrillic correctly before you meet it in a full
sentence.
A reasonable place to start
Learn the four Ukrainian-specific letters — і, ї, є and ґ — before anything else, since they are the ones most likely to have been taught wrong by Russian-labelled material. Then spend a deliberate hour on the five false-Latin letters, в, р, с, н and у, reading them aloud until the correct sound arrives before the instinctive one does. Everything after that is vocabulary, not alphabet.