About 15 years ago I had my fisrt students of croatian for foreigners. Those were some French people who lived in Zagreb and an Australian girl travelling the world. I started doing in person and online croatian courses.
In the meantime, most of my courses is online, however, I also offer the possibility of in-person classes in Zagreb.
Since most of my students are not from Slavic coutries, I believe that a systematic approach to learning Croatian is the best way to learn the language. This includes learning grammar, vocabulary, syntax and pronunciation.
For my classes I use the Croaticum textbooks which give a systematic approach to learning Croatian language.