1. As much as you love your new spouse, you will miss your parents terribly.
I learned this as soon as we drove away from the airport after our honeymoon. I was so used to getting to ride home with my parents and regaling them with my adventures. That didn't happen; I rode one direction with my new husband and they drove another direction. I cried. It was awful because there was proof that I wasn't going to live with my parents anymore.
Sidenote: I still cry some times.
2. The first time you go grocery shopping, go together. You'll need the moral support.
It was the first time I had to shop as a wife, the first time I was in charge of feeding someone and keeping a home. We needed food for the week, but we also needed the cooking basics: flour, sugar, vanilla, spices, milk, etc. That list was long enough, but that was the food list alone. I had another list for cleaning supplies like paper towels, dishwasher tablets, Windex, etc. If you can imagine a list that starts unrolling and never ends, that's what I thought this list was. Lyndon offered to come with me and saved me. He found things, thought of things I hadn't, and helped me keep track of everything. Altogether it took a very long time, but I would have been there until the wee hours of the morning if Lyndon hadn't been there.