Croatian offers several ways to greet people depending on the time of day and the formality of the situation. The most versatile greeting is Bok, which works both as a casual hello and as a relaxed goodbye, much like "hi" or "bye" in English. For more formal or daytime encounters, Dobar dan (Good day) is the safe choice, while Dobro jutro, Dobra večer, and Laku noć are used respectively in the morning, evening, and when parting for the night. When saying goodbye more formally, Doviđenja is appropriate, and when seeing someone off until later you might add Vidimo se sutra (See you tomorrow).
Politeness phrases are short and easy to memorise. Molim means "please" but also "you're welcome," and it can be combined with te or Vas to address someone informally or formally. To thank someone, Hvala is the everyday word, and Hvala lijepa adds warmth, equivalent to "thank you very much." The response to thanks is Nema na čemu (literally "there's nothing to thank for"), which corresponds to "you're welcome." When you need to get attention or apologise, you can use Oprostite (Excuse me, formal) or Žao mi je (I'm sorry).
For basic yes/no responses and politeness markers, Croatian uses Da for yes, Ne for no, Možda for maybe, and Naravno for "of course." The negated form Naravno da ne serves as "of course not." These little words come up constantly, and pairing them with short phrases such as Da, slažem se (Yes, I agree) or Ne, ne mogu doći (No, I can't come) lets you respond politely in most everyday situations. Master these and you can already hold a very basic exchange.