There is a fair amount of research indicating that attention to form (e.g. grammar) is important for second language acquisition. Krashen and others claim that one can focus on meaning only, and grammar acquisition will come naturally. This claim is quite popular, and case studies (e.g. some kid named Wes) and anecdotes appear to confirm this is at least possible. Later researchers claim that attendance to the language code is more effective in acquiring grammar than focusing solely on the message for adults learning a second language.
"For successful grammar acquisition, attention to form is probably
necessary. This attentional focus on form can be externally achieved by
instruction or internally sought by self-study and self-directed analysis of
the linguistic material available in the environment.
Grammatical competence appears to evolve in ways that are less amenable
to incidental benefits from the environment than other aspects of the
language to be learned, such as vocabulary, discourse competence, and so
on. It also seems to hold a special status in language acquisition. Specifically,
grammar (a) requires more interest, attention and hard work than other
aspects of the language to be learned; (b) may even require more time to
simmer and deploy than the learning of other aspects of an L2; and (c ) can
act as a gatekeeper to development in other areas of the L2 beyond formulaic
repertoires, particularly sociolinguistic competence."
from Understanding Language Acquisition by Ortega (2013)
Currently I think my biggest potential areas for improvement are probably (1) having good heuristics for what to pay attention to in input; (2) maybe exploring repetitive listening if I can find a good reason to.
For (1) I think that forms like grammar, conjunctions, discourse terms, sentence structure, etc probably deserve more of my attention, and vocabulary probably deserves less of my attention.
For (2) I have a gut feeling that repetitive listening could have lots of benefits, but I’d like to have solid evidence that it’s effective because it would be very time-consuming. For example, the first time I watch an episode, it takes a long time, and most of that is just trying to determine what was said. Maybe the 3rd or 4th pass is better for truly practicing listening comprehension.