1. Pay attention to which ideas, nouns, terms, abbreviations come up more often, indicating they are the "table stakes" for a particular area of tech.
2. Develop a personality trait that refuses to stay satisfied with "not knowing". Practically speaking, this means: set aside dedicated time each week for self-study of the concepts you've taken note of in the first part and skip other things, but don't skip this.
3. Take notes when reading or consuming video/podcasts that cover these concepts and I sincerely recommend the practice of writing your notes by hand. There's no magic to it, but (I imiagine) the slower process of writing aids the mind in putting what you consume into your own words (and associating it with other things you already know in the field).
Here's an example from way back -- before phone apps, before web apps were common, I used to create full stack systems (backed by databases I designed) in "thick client" GUI apps using Visual Basic. But the concept of web apps was gaining traction and I wanted to figure out the key ideas. The main thing I hadn't figured out was how the heck data fields from a web form (for example) could be reliably relayed to the "business tier" of a 3-tier web application. People threw the term "request object" around like it was some kind of obvious concept. I simply had no knowledge that all frameworks/libraries for web application development provided this common request object abstraction, so I was imagining all kinds of complicated and proprietary ways one might need to construct such an object -- especially across different web servers.
I have noticed that this kind of "getting stuck" is common to the self-taught. Following the process I mentioned above, I focused in on learning about the popular web server APIs such as CGI, NSAPI, and ISAPI and how popular frameworks (at the time) such as PHP or ASP made accessing them much more developer-friendly through already-created request objects.