I've learned to put up a few signs around the place too. Sometimes I am not able to meet guests until the day after they check in and occasionally our paths do not cross at all. Signs usually(!) prevent problems - assuming people actually read them! Here's what I have:
* The rubbish/recycling one (with a reminder to wash the cans/bottles first - to deter ants and yeah, fish reeks when left in the wheelie bin for the bi-weekly collection) and one for compost. Note to self: If guests ask if paper goes in the recycling, it is a good idea to confirm they are not asking about (used) TOILET PAPER!
* Certain demographics get the This is not a Squat Toilet pictograms.
* Others have to be reminded that there is no drying rack at the top of the cupboard (they are used to having a fan/vent system at ceiling level in the bedroom cupboards, and automatically hang their wet towels etc as high up as they can get them).
* Most guests walk straight past the hutch in the dining room, open every cupboard in the kitchen and ask me where the plates are. Even after putting up a sign "Plates are over here" and an arrow pointing to the hutch, about half are still confused!
The signs which occasionally annoy guests "We are not kindergarten kids!" (although more often, they are pleased with) are the ones on the kitchen drawers/cupboards. These let guests know where they can find cutlery, chopsticks, strainer (lots of guests cook pasta) etc.
I put those signs up a few months ago after noticing a very polite but very shy guest ate nothing but sandwiches for a few days. When I told her it was OK to use the kitchen, she said apologetically "I don't know where to find anything and I don't want to open everywhere in case I used your things."