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.
Are you social enough that you could attend a protest or something in your area? Could be a good place to make friends whilst standing up for your beliefs and taking, at the very least, some actions toward them.