seaweed

I think a mixture of both approaches is the best. Those that learn by immersion, like you, don't learn the "rules" and may end up using incorrect grammar without realizing. It's harder to self-correct, and most native speakers are unlikely to correct awkward phrasing unless you ask them about. At the same time, if you focus too much on learning the theory it can get very overwhelming just trying to talk. And I think you need to get a "feel" for how things are constructed to speak comfortably.