I think that putting posters in bathrooms, or even just sticky notes that say "Free Palestine" would be underwhelming although enough people doing it would probably catch attention. With the internet, it is very easy to spread proletarian news or ideas but liberals still reject it on ideological grounds and loyalty to the status quo. What are some methods of praxis or propagandizing a person can do alone in real life, without an organization, and somewhat clandestinely? Please don't say anything online would make it more difficult for you or other revolutionaries to do it successfully in the future.
If you mean "without an organization pre-existing," the answer is obvious: start an organization. It'd be much easier to join one, but your stipulations are your stipulations.
If you mean "without an organization at all," then the answers are "have money" or "do adventurism*" because there simply isn't much you can do outside of an organization
*disclaimer: I don't mean blow something up. Actions like what you describe with the stickers is also a type of adventurism if it's not part of some sort of systemic campaign but just you "redecorating".
On a more positive note, since you're interested in the topic of propaganda and rhetoric, here's my favorite essay:
https://redsails.org/masses-elites-and-rebels/
Do you know of any good literature on adventurism specifically? I have a general idea of it in broad strokes, but would be helpful to read more about it in detail from revolutionaries past or present.
Here is Lenin on it briefly and at length, though the former is more about adventurism generally and the second is about an attempt to rehabilitate it.
Thanks! I'll look at those.