Now at 30ish, I find I can learn languages MUCH easier. I speak fluent french and am reasonably conversant in Spanish. (I can read it pretty well though.)
We tend to focus on reading, oral understanding & writing. Those fit easily into "sit down and study for 45m" format. Speaking doesn't, and can feel uncomfortable or contrived in classroom settings. One of the big reasons "immersion" often leads to fast breakthroughs is because it comes with a lot of natural speaking. That's often the bottleneck.
You don't stop and think of the correct grammar, words or whatnot when speaking. You just try to make yourself understood as best as you can, with whatever language skills you have. Even 200 words is something. Engaging that intuitive improvisation can be really helpful.
Yes, at some point you'll need to work on pronunciation but that is something different than the type of extemporaneous speaking we are discussing here.
But this probably only goes to show what another commenter pointed out, which is that there is a lot of conflicting advice out there.
-Spaced repetition
-Lots of exposure
That's it. The rest is up to you. Some people swear by their specific app, some people religiously study their Assimil handbook, some people will argue that you should never ever learn grammar, some people swear by total immersion, and Nassim Taleb (who speaks like 7+ languages including like Ancient Greek) just reads a lot of books, but ultimately little of it matters insofar as it does one of the above two. There's an overabundance of learning materials out there for you to grab and use, just have your pick and find what's best for you.
Oh, and it goes without saying, but like with all learning, or indeed all cognitively demanding tasks, you have to actually want to learn. Ideally there should be an external motivator that pushes you and from which you can feel rewarded as you learn, this can range from 'watching anime without subtitles' to 'speaking with your SO in their language' but it has to be something.
But here are my tips: Immediately start by thinking in the language, or at least in terms of grammer. If you think about it, recalling and using words to say stuff you want is one of two primary skills you actually want to develop, so you need to actually practice that. Even if you do this with incorrect grammar, it's still incredibly beneficial. (German is a bit harder grammar-wise, but that's ok, you need to learn to think in the German grammar pattern before you can speak German.)
What does that really mean though? A couple of things: When you think about something you want to say, think about it in terms of grammar. Instead of thinking "I want to go to the beach", think like this: "[pronoun for me] [conjugation of verb "want"] [infinitive "to go"] [noun "the beach"]" Once that skill becomes a habit, speaking is trivial. It's just vocabulary. A note: I will think in terms of bastardized English grammar so that the grammar I'm thinking in conforms to the language I WANT to be speaking or understanding.
Here's an example: If I want to translate the phrase "I want to do it" to french, I'll think in the french grammatical pattern first. Then I just fill in french words if I know them, or english if I don't. Let's suppose I don't know ANY of the french words yet. I'll think; "{I [want]} [it] [to do]" because that's the correct order in french. "{Je [veux]} [le] [faire]".
To practice this, Learn a couple dozen words and a few phrases. Think about every possible combination and modification you can make with those and practice with imaginary conversations in your head. Then start to generate new things, and fill in the gaps with what you do know. This starts to practice the pattern of filling in words you do know. If you don't know them, guess. Look them up. Gesture. You're trying to communicate not do some abstract thing.
A side effect of this, is that it can be a real bitch to switch between languages if you're out of practice. I sometiems start thinking in the wrong grammatical pattern but filling in words from English. It can be pretty funny.
Although I do observe kids having superpowers when it comes to learning stuff, especially language, I find that the primary learning barrier for me is, as ever, time and interest.