By far the most effective way to learn a new language is by complete immersion. That means moving to a new country and ONLY speaking your new language. The most important part of the process is to refuse to speak your native language. Often when studying abroad (especially for english speakers) the local populous will recognize that you're not a native speaker, and if they speak your native language they will use it in an attempt to communicate with you. While this is nice, it drastically undermines your language learning efforts because complex conversations where you would be learning the most will be conducted in your native language. If you can commit to complete immersion, you will be surprised at how fast you can learn. Take these guys for example, who learned 4 languages in a single year.
Not ready to uproot your life and move to another country? I can't blame you. The next best way to learn a new language is to simulate immersion by using the new language as much as possible. Read books in the language, listen to podcasts, change your Netflix settings to only play shows in the new language (and watch them without subtitles in your native language), find friends that speak the language and ask them to refrain from using your native language when speaking with you. There are several good services that help with language immersion including LingQ and Pimsleur.
No matter how you choose to learn a new language, you'll have to memorize a lot of new vocab. By far the best way to learn vocabulary words permanently is by using spaced repetition. Spaced repetition is a studying technique used mainly through flashcards, where you study cards less and less frequently as they become easier for you to remember. This strategy mirrors our natural tendency to forget things on a predictable schedule. There are several good options for spaced repition out there. You can download our app for free, or use a product like anki, which is free to use on a computer, but the iOS app will cost you $25.
At the end of the day, if your goal is to learn a new language, having conversations is imperative. You can know all of the vocabulary, but if you haven't practiced speaking, it won't matter. Try finding friends in your area who speak the language, or you can use a service like italki to have conversations online. You can even use ChatGPT to practice!
