I wouldn't worry about doing or saying specific things. There is a temptation to make grand gestures. Don't worry about all of that. Spend a lot of time with her and just be yourself. My mom spent the last month of her life seeing people and helping them deal with the fact that she would be gone soon. She focused on making sure that we were as prepared as we could be for her being gone. It was weird and sad and great all at once. The time we spent together was, despite the obvious differences, very much like the rest of our lives together. We got angry, we got sad, we laughed...in short we lived. Nothing was left unsaid. When she did die I was sad for myself but happy that she was done with her ordeal.
Videos are great but again I would focus on keeping it simple. When I watch the few videos we have of my mom I am far more interested in seeing and hearing her than what she is actually saying. I'd rather have a video of her just interacting with people and having fun than a video to me specifically.
What I miss the most are the daily interactions with my mom. I can't have those again but having ways to re-create the experience her being "around" is what means the most to me. Your daughter will have a lot of people to give her advice...what she'll miss is experiencing you as a human being. Maybe you can give her that by just recording your life with her and your family. She is smart and insightful and she'll get what she needs out of it when she needs it.
I wish you all the best.