1. You are a stranger in a strange land.
Think of your time with your new in-laws as if you're traveling to a foreign country. His family's traditions and customs will be different from your family's. Have respect and remember that they've functioned perfectly well for generations their way. Don't go in guns-blazing to try to make them more like yours.
2. They speak a foreign language.
You may all be speaking English, but as a newcomer, you can't know the subtext of what's going on in a conversation: the meaning, intent, and history behind the words spoken are unknown to you. Don't assume you understand the deep meaning of your father-in-law's "Hmmm, that's interesting."
3. They have different body language, too. When your mom looks at you askance, you know exactly what she's getting across. Your MIL? You haven't a clue what her raised eyebrow means. Don't assume it's the same message as your mom's raised eyebrow.
4. Let your spouse be your tour guide.
After a lifetime of living with them, your partner can read the situation, the mood, and the nuance far better than you'll ever be able to. For example if your partner says, "Hey, let's not push this point right now," or if he or she lets you know that showing up even just 15 minutes late to dinner with your in-laws is not cool, take the advice and adjust your behavior. If you're in doubt about what is going on, ask your partner to explain.
5. Let your partner take the lead.
It's best to have your fiancé make the plans with your in-laws and lead the difficult or delicate conversations with his parents. Weekly phone calls to say hello can be a great way to encourage a relationship (and all you have to do is just pop on for a quick "hi"). Conversely, you can take the lead with your family, so that it feels equal and balanced.
Allison Moir-Smith is an author and bridal counselor who specializes in engagement anxiety and cold feet.