1. Bring something
Pick up a bottle of your favorite wine, whip up your signature pumpkin rolls, or greet her with a pretty arrangement of flowers. This small gesture will not only make you look good, it will make your fiancé look good, sending a message that you two are true adults—a vital point if you want to be treated with respect.
2. Keep mum about your Paleo/gluten-free/raw diet
Ok, we get it, you like to eat a certain way, but that doesn't mean you have to announce it before every bite. Or worse, decline to taste your future MIL's famous pecan pie. Whatever you do, do not evangelize your way of eating. The rule of thumb: unless someone asks about your eating habits, keep your opinions to yourself.
3. Nod your head and carry on
Whether it's your first, or fifth, Thanksgiving with his family you'll probably be bombarded with tons of questions about your personal life as a couple: When are you having a baby? Are you really going to go back to work after you have said baby? Why don't you visit more often? You know the spiel. It's easy to get annoyed when Aunt Susan keeps asking about your reproductive plans. "Some older people think if they ask you 400 times, you'll have a baby just to shut them up," adds Alkon. A verbal attack can set off a fight-or-flight reaction, and you don't want to lose your cool. Come prepared with a handful of stories to deftly change the subject.
4. Talk to elders (and youngsters)
Seek out people who are not already the center of attention, like Gram-Gram or his 13-year-old nephew who's bored with all the adult chatter. Take note: it's easy to yammer on about yourself, especially if you're nervous, but this is the time to engage and perk up your ears. Asking Granny about the first Thanksgiving she hosted will not just score you major brownie points, it will give you a better understanding of your fiancé's family history.
5. Leave the phone in your purse
Even if everyone else updating their Facebook status, refrain from looking at your phone. One of the major tenants of Thanksgiving is togetherness, so it's important that you're present the whole time, engaging with real people, not virtual friends.
6. Respect everyone's privacy
Ask before you post any photos on social media. Not everyone feels comfortable having their baby's pic on Facebook. And, posting a photo where you look radiant and your sister-in-law looks drunk because her eyes are shut is not going to make you look good in real life.
7. Return the favor
While it may seem like a given that you should be invited to Thanksgiving at your in-laws, don't take it for granted. Show your appreciation by treating everyone to breakfast the next day. Research shows that when we show gratitude, we are actually happier. Win-win!
8. Help out before, and after, the turkey is served
Sounds like a no-brainer, but don't just say, "Do you need help?" Offer specific assistance, for instance: "I see that the cheese tray is running low on crackers, want me to restock?" Once the festivities are over, team up with your partner to clear the table and do the dishes.
9. Write a thank-you card
Listen, your MIL didn't just set out a bag of Doritos and beer in front of the TV. As we all know, hosting Thanksgiving is a big undertaking (and we're pretty sure your MIL wants to impress you as much as you want to impress her). Thank her properly by sending a note highlighting the best parts of the day. You want it to be an actual card, not a quick email message you typed up between texts.