Fluency in Croatian depends not just on vocabulary but on the small phrases that organise a conversation. To give your opinion you say Po mom mišljenju (In my opinion) or Iz mog kuta gledanja (From my point of view). To signal uncertainty you might use Koliko ja znam (As far as I know) or Nisam siguran (I'm not sure), and to soften what you say you add Iskreno govoreći (To tell the truth) or Čini mi se (It seems to me).
Linking ideas is done with a set of discourse connectors. To introduce examples you use Na primjer (For example); to add information you say Osim toga (In addition) or Štoviše (Furthermore); to contrast you use Naprotiv (On the contrary), S jedne strane (On the one hand), and S druge strane (On the other hand); and to rephrase you say Drugim riječima (In other words). A conversation can be summarised with Ukratko (In a nutshell) and qualified with U svakom slučaju (In any case) or Ovisi (It depends).
Other fixed phrases handle time, urgency, and everyday reactions. Što je prije moguće (As soon as possible) and Krajnje je vrijeme (It's about time) deal with timing, while Korak po korak (Step by step) and Jednom zauvijek (Once and for all) describe how an action should unfold. Prije ili kasnije (Sooner or later), Vrijeme će pokazati (Time will tell), Dugoročno (In the long run), and Kratkoročno (In the short term) let you comment on outcomes. Conversational openers include Usput rečeno (By the way), Kad smo već kod toga (Speaking of which), and Kad bolje promislim (On second thought), while reactions cover Imaš pravo (You're right), Šteta je (That's a shame), To ima smisla (That makes sense), Nije važno (It doesn't matter), Pazi! (Watch out!), Dosta je (That's enough), and Jesi li ozbiljan? (Are you serious?). To ease the mood you say Polako (Take it easy) or invite someone with Osjećaj se kao kod kuće (Make yourself at home); to take time you say Daj da razmislim (Let me think), and to comment on surprise you use Iznenada (Out of the blue) or Ne isplati se (It's not worth it).