[quote]2 of the situations were people that didn't depart at the time they were supposed to[/quote]
I keep a sign on the door that says "Check out 12 noon". For the people who think that 12 noon check out is kind of like "no more than 10 items in this line" and like to bend the rules, you could leave a note in the room explaining WHY it's so important that they check out by 12 noon -- You have to get ready for the next guest who is arriving in 3 hours!
Unfortunately you can't really do much to screen out the haphazardly guests. I would like to reject people under the age of about 23 but that would expose me to an age discrimination lawsuit.
If possible, consider turning your room and bathroom into closed off in-law unit. That way you at least don't have to share interior space with these people.
Another strategy to get better guests is to lower your price to the point that people book a good 3 to 12 weeks in advance. Careless people don't tend to book that far in advance.
BTW some of my most respectful guests never mentioned what they were in town for. They leave just a short note when they book like "Looking forward to staying at your place".