Say it. Wolgemuth suggests, "More often than not, these kinds of things break down based on what is not said, not what is said." Think about that huge tirade that you save up for your spouse as soon as the car door shuts and you're pulling out of the driveway at your in-laws' home. Examine the recurring themes, and prayerfully consider what you might need to address with your in-laws. None of us like conflict, but without conflict and resolution, healthy relationships do not exist!
Deal with it early. November and December are not the times to spring plans or sit down for a "discussion" with your in-laws. Let your in-laws know about your holiday plans in the late summer or very early fall. If you have issues that need to be addressed, make a phone call or write a letter now so you can spend the holidays celebrating.
Adjust your expectations. Let's be realistic: none of us will have a "perfect" holiday. The turkey might not be done on time, a child might have a grand mal tantrum, and Uncle Toney might show up with his "special friend." If you picture a Hallmark movie going into the holidays this year, you are going to be disappointed. Instead, make room for reality and look for things at each celebration that you can laugh about and be thankful for.