As markthespark says.
Get yourself out there, contact firms, contractors, ask friends, friends of friends etc. E-mail them a covering letter (was going to say CV but do you have one?), phone them, visit them in person. Sell yourself.
Personally I WOULDN'T offer to work for free but that's me.
Do you have any electrical academic qualifications? At your age I'd enrol at college for the City and Guilds 2330. It's a 2-3yr course, one day OR 2-3 nights a week. Once your on this and if your still looking for work I think you'll find employers will look upon you more favourably.
Finally, visit this site regularly. You can find LOADS of information on here (I have) and the guys (and girls) are very friendly and always willing to help.
I hope this has helped some, if you have anymore queries, let us know.