Start learning from day one, even if you already speak the language. I speak Dutch fairly well. Without any configuration, when I first opened Phrasing, the first word I learned in Dutch was vermomming・disguise. Immediately contouring provided value.

Acquire the basics naturally. When speaking in a foreign language, you want the basics to just roll off your tongue. You don't want to have to be thinking about tenses and conjugations and word order and prepositions; these thing need to just flow. Since they will need to be acquired anyways, just leave them to be acquired.

Memorize words that need memorization. Memorization gets a bad rap, but there are huge swathes of vocabulary that can benefit from being memorized. Essentially, every word you study in spaced repetition you are memorizing. So save that for the words that need it most.

Develop a a useful vocabulary immediately. Every single day, I can find some useful Macedonian vocabulary to use, despite just having Macedonian friends. I've been able to understand and say substantially more Macedonian than any other language I've studied for this amount of time. Am I only picking up and saying a few words? Absolutely. Am I forming complete sentences? No. But which would you rather be: effective or grammatically correct?

Practice ambiguity. What nobody tells you about learning another language is how long you have to deal with ambiguity. Practice early and practice often, and you'll be miles ahead of others even with your same language level.

Understand natives sooner. True story, the first word I learned in Macedonian was bazhna・important. The very next day, a Macedonian friend of mine was talking to dog telling him how important he is, as my whole house has been adapted for him. I know this, because she used the word bazhna several times.

Higher leverage words are… simpler? It sounds counter intuitive, but most of the complexity in languages comes in the most common words. Prepositions, articles, to be, to have, counting words, etc.

Review large swathes of language on your own. At some point, with any SRS, you'll start to memorize flashcads. By learning and studying fully complex native level sentences, that means you can review large amounts of language anytime, anywhere, all in your mind. You can practice pronunciation, dive deep into grammar, and review dozens of vocabulary words and declensions without even pulling out your phone.