this can definitely be really tricky. If you want to start out subtle, I suggest making motions to clear away glasses, dishes, etc. and start tidying the room a bit while saying, “Well, this has been a lot of fun; we’ve really got to do it again soon!” With any luck your guest will take the hint and leave. Some people, however, don’t get subtle and need a more drastic method called honesty. That would be something like, “Thanks so much for coming; I have really enjoyed your visit but I do look forward to seeing you again soon.”
This can be accompanied by walking them to the door, handing them their jacket, and generally acting like it was their idea to leave.
There are, remarkably, some humans who are dense enough not to understand even this kind of directness. For them, one must crank the honesty level. Don’t be cowed or discouraged! It’s your home and you get to decide when the visit is over.
This is not rude; it is being proactive about your needs and your time.