For example: Whenever you walk into a store, ask if they accept BTC or cryptocurrency etc. ? Even if you know they don't. It primes the cashier or manager to better acknowledge the next customer who asks a question like this and also starts a conversation or beginning to something new.
What would be your idea?
Your idea might help promoting bitcoin but I guess if you are the only one who will do that and nobody seconded it will just end useless and will just forgotten, the best way to promote bitcoin is through advertisement and through educating our friends and love ones. I guess this will leave impact rather than promoting it to someone you do not even know.