The difference is to do with whether you are talking about specific things or things in general.
In the case of memes if you are talking about memes in general you would omit the article as I have just done, and you can refer to a subset of memes without the article as well (you can talk about 'cat memes' for example without using the article) but if you want to talk about a specific meme (say the flat earth meme) you use the article. This is generally true, if you are talking about a single thing you use the definite article (unless any one item will do as in "I would like an apple please" where you use the indefinite article), the problem only really arises with plurals.
It gets more difficult when you are talking about multiple things as in the Elon Musk quote "Who controls the memes controls the Universe." because it can be difficult to decide whether you are talking specifically or generally. In Musk's case he was talking about all the memes that exist or might exist but he was talking about them in a specific way rather than a general way. It would also have been possible for him to say "Who controls memes controls the Universe" and it would still make sense but it would not have been quite as powerful and there would have been a mismatch between the general memes and the specific Universe.
In general I would suggest that you follow your instinct but, if in doubt, use the definite article rather than omitting it, there are more cases where you are talking about specific things than general ones. Also keep listening to and reading English and your instinct will improve.
Sorry I can't help with a rule, I don't think that there is one.