Getting good grades shows that you are not a loser and can learn.
Not to disrespect anyone who got bad grades because so did I.
Mainly because I wasn't there, not because I couldn't learn.
If someone came to me wanting a job from school, they'd have to
have a good attendance record from
school, and decent grades.
Ask your school about a work experience program as well.
Going to your local locksmith dressed not like a bogan,
nor like a rapper or a businessman and asking to
help out in the shop is a yes or no answer. 50/50
chance of an opportunity, so take it.
maybe learn as much as you can about locks and their
inside bits, how they work, a little bit of basic
terminology will help, he may ask, "Have you ever
disassembled a cylinder...?"
"Do you know why a plug doesn't turn without the key?"
If you at least know what he/she is asking, that
is a start.
Never pretend that you know more than you do.
You will learn this stuff by reading the MIT Guide to Lockpicking,
http://www.lysator.liu.se/mit-guide/mit-guide.html
checking out this site by Deviant Ollam:
http://deviating.net/lockpicking/topics.html
Bookmark these pages onto your computer.
Reading this site and asking questions on this site
after you have searched the site yourself and still
not got the answer you need. (unlikely)
Good luck with the apprenticeship, dude