In general, tidy up, open up and unclutter. In short, get the whole place ready for close inspection. Greet prospects politely and excuse yourself. Leave the selling to the agent. Agents know what your house has to offer and what these particular buyers are looking for.
Agents also know how to sell.
Don't try to interrupt with suggestions, such as what personal property you might sell, what kind of financing you think would be good for the buyer, etc. Don't apologize for imperfections, but answer all questions put to you briefly and honestly.