Congrats! Make sure your FI wears dark socks...I didn't think to tell my husband this when we took anni pics recently and he wore white socks! When we were sitting on the ground his pants were a bit shorter and the socks really stuck out! I had
to camoflage them in leaves lol.
Also, do some looking online and find some poses/shots you really love. Email them to your photgrapher ahead of time if you can, I did and she brought a really cute chair with her to do a few that I would not have thought of. At the very least
print them out and bring them with you...I did that for my wedding and she used those as a reference the entire day to make sure she was getting everything I wanted.
Plan your outfits ahead of time. You don't have to have anything super fancy, sometimes simple jeans and a cute top are enough, but you want to look nice and not clash with FI.
It doesn't hurt to get your hair professionally done. I went to Cost Cutters for something cheap and easy and they did a super cute side-swept curly pontytail that didn't look like it had been professionally done and wasn't over the top for anni
pics, but it was way nicer than anything I could have done!
Have fun!! Relax, enjoy being with each other. Talk with each other, laugh, touch each other's faces, arms, etc...a photographer will be able to capture all of that and it makes for some natural, beautiful pictures!