Become VERY proficient, very versatile and be a quick study. You will be working with different entertainers and different programs constantly. You will need to effectively improvise. Watching the skilled band members on my cruise gave me a great appreciation of how much farther my 14 year old daughter (trumpet/clarinet/sax) has to go before she is the professional she hopes to be one day. I would think all the workshops, camps etc that you can attend would be helpful, as well as private tutoring. Of course, this is the prep for any professional career, which is what you wish for. Get a lot of experience with your local community musical groups, and I would suggest also musical drama etc as a good training ground. The show band on my ship was everywhere, accompanying every act(it seemed), backing up musicians, magicians, hula dancers. . .they were a very skilled group. Frankly, all the band members were male, and seemed at least 30'ish, but I don't imagine they care as long as you have the skill, talent and experience that they need.
Good luck-its wonderful to work for a goal!