With the holiday season just around the corner, it is common for people to meet their significant other's parents and family. Even if this is not the first time you are meeting them, the impression you leave on them around this time is important.
Most people make their first impressions within the first three seconds, so make sure that you are dressed appropriately. Ask your significant other how dressed up his/her family gets. Some families were jeans and sweaters whereas another one might wear dresses or slacks.
If you are going to the family's house for dinner, always offer to bring something. If his/her mom is cooking, it shows that you are thoughtful to want to contribute. If they say bring whatever, a pie or some desert usually works great. Some places might say wine, but depending on the families' view of alcohol, this could be completely inappropriate.
It is also important to offer a helping hand. Whether it's help in the kitchen, setting the table, anything, it again shows that you are thoughtful.
Remember that the holiday season is all about family and giving thanks. Being polite is important, but relax and be yourself. Your significant other probably would not have invitied you if they didn't think you would do great!