What to find out in advance: Which relatives will be there? Will you be responsible for any meals? Will your family be going to or hosting any parties? Who’s sleeping where? (If space is tight, consider staying at a hotel.) If you have kids, do you need to bring any supplies?
What to give:

A gift-wrapping kit with paper, tape, and ribbons for last-minute presents.

If there’s a fireplace, starter sticks, pinecones, and a box of long matches.

Evergreens and holly for decorating.

If the kitchen will get a lot of use, bring a set of nice dish towels and a scented dishwashing soap to make things pleasant for the cleanup crew.

What to do:

“Offer to pitch in with chores, and behave as houseguests even though you are family,” says Margo Howard, author of Slate’s Dear Prudence online etiquette column. “Host is not synonymous with maid.”

When you’re spending an extended period of time with the extended family, everybody needs some time apart, says Howard. Planning a few escapes on your own can help relieve tension.

Coming and going: Run arrival and departure times by your hosts before reserving tickets or cementing plans. Try to arrive before their bedtime, or ask them to leave you a key. When you depart, strip your beds and deliver sheets and towels to the laundry room.
How to follow up: Arrange for a massage therapist to come to the house after you’re gone and leave a thank- you note with the details, or give them a gift certificate or two to their favorite restaurant, suggests Robyn Freedman Spizman, author of the gift-giving handbook Make It Memorable (St. Martin’s Griffin, $12 on www.barnesandnoble.com).