Your best assett is yourself. You have to go in confident and sell your past experiences that can be related to this trade. If possible get on the books as a groundman and go on the crews and learn as much about linework as you can. Find a lineman to mentor you and ask many questions. In this apprenticeship you will need good math skills, physical abilities, positive attitude and a great desire to learn. Letters from past employers and co-workers is helpful too.
I wish you luck and hope you do well. This is a great trade to be in!