Personally, this is how I learn new languages, and it's a combination of two methods.
1. On a need-to-know basis:
I have a crap memory (probably small brain), and so, with most things in life, I learn them as I need to know. Language is no different. I learn stuff on the need-to-know basis, and over time, organically, I do end up with sufficient knowledge to operate. Some things organically repeat on the need-to-know, so eventually, it enters my long term memory, because my mind registers that knowing that is quite important.
2. Hobbies/using a hook:
It's no secret that I like to eat, so I wind up with a rather extensive vocabulary revolving food in several languages. Sometimes, when certain languages are fairly similar, e.g. romance languages, I then create mental maps to map certain languages to something else that's already more ingrained in my mind. My friend describes this as the "inkblot" method, where you link new things with things you already know, so it sticks a bit better.
Thanks for sharing this with us. I'm glad you have found a way to learn a language that works best for you. This is helpful and gives me some ideas too. Good luck in all your journeys!