These are not necessarily something you should memorize word for word. Often memorized lines can come off as stiff and unnatural. Ideally for your shoot you have a list of bullet points you want to cover in each video. You want to practice using those as guidelines and speak off the cuff as you deliver your message.
Practice doing this in a mirror until you are comfortable with your presentation. Then, practice some more! Try it in front of a colleague or friend, or even use your smartphone to record a video of you rehearsing so that you can get feedback and judge your performance. Make sure you bring your list of bullet points to the set with you so you can reference them between takes as well.
You want to try and look your best on camera. A good rule of thumb for clothing is to never wear something you have never tried on before, or do something like get a haircut the morning of the shoot. Here are some other things to keep in mind while you pick your outfit:
This applies for women and men. Wear your make up as you normally would, or if you don’t wear make up do a few tests before the shoot to see what looks best. If you won’t be wearing make up, at least consider powder, which will remove ‘shine’ and take care of small beads of perspiration that you get from being under lighting. If you are against wearing powder too, then bring a towel with you to help minimize shine.