Obviously, if fresh flowers were placed in your room on arrival, nobody will be expecting you to replace them before leaving but on the whole, make sure the room is in the same condition as you found it.You won't be expected to vacuum and dust but you should always make time to tidy. Anything you took into the room should either be taken home with you or disposed of.
If it was untidy and cluttered when you arrived it's ok to leave it in the same state. Just don't add to the clutter by leaving your own belongings behind.
Send A Thank You Note
A couple of days after leaving, send a note thanking your host family for their hospitality and telling them what an enjoyable time you had. Make a point of mentioning specific events such as:
I especially enjoyed the ballgame on Tuesday evening even though I usually avoid them like the plague. Johnny certainly has his father's talent!
Your homemade apple pie was the best I've ever tasted. If you don't mind giving away the recipe, I'd love to know how you get the crust so flaky.
Being able to relax in such a beautiful garden was great after spending all year in this city apartment. Ed really knows what he's doing with those roses.
You get the picture? Let them know it was the time you spent with them that was important.
By following these tips you'll not only be making life easier for your host family, you'll find yourself enjoying being a house guest far more than you would ever have expected. Don't dread your weekend away -- see it as a way of getting to know friends and family on a more personal basis, instead.