The only way I made progress in latin was when I bought a few books and started reading, beginning from (modern) children fairy tales. This actually gave me a lasting knowledge which up to this date allows me to read a simple latin text or guess a meaning of a word in English or French (neither language is native to me).
Speaking latin of course takes it way further but I think the direction is the same: learn it as a living language not as as a dead one. Starting from declensions and cases gets you nowhere, judging from my friends who learned it in school for years with zero results. Instead, start using the language, if only for reading. Then you can return to grammar later if you ever want to become proficient.
I also recommend this guy [1] who not only shares the same approach but apparently have fully dedicated himself to it. He has books, ebooks, audiobooks, a mobile app and a youtube podcast, all in latin. I can't cease to be impressed by the effort and the quality of the content. In comparison the Duolingo latin course is a complete disappointment.