That's a very kind thought, and I'm sure the crew would appreciate a gift from you. Might I suggest a box of good quality individually wrapped chocolates? Enough for say two per person or so? If they were something local, rather than a worldwide brand, that would be great. Yes, they are doing their job, but sometimes something immediate can make someone's day.
As for the nervous flyer part of your post, you would possibly feel better if you know what's happening. Can you get a copy of a simple book on the way aeroplanes fly? There are quite a few available, and one was recently linked in a post on this forum.
Most of all, relax, get comfortable, and look forward to your trip. Personally I enjoy a G and T before lunch when being a passenger. Then I sleep after the meal.
Have a great time!