Best thing to do might be to look into interest groups in your area (whether they be IT-security or just general IT-related,) and start networking there.  You can also check in with local schools, to see if they are aware of any co-op positions, or even places where you can volunteer, just to get your foot in the door.  I found that I had to give some 'free' time, at a couple of points in the past, to work my way into certain positions.

As far as starting points, if you're freshly getting into IT, CCNA and other baseline certs are good.   It's definitely a plus to get yourself some networking background, understand protocols (like TCP/IP) and routing, and get fundamentals under your belt.  Without them, a straight move into security / pentesting isn't impossible, but can be harder, if you don't really understand those areas.

Edited - Sorry, just referenced your older posts, and see you're from the UK.  So I had to edit this paragraph a bit, from my original reply.  Some folks here at ethicalhacker.net might be able to help point you to some opportunities, although I don't personally keep a list of those in the UK.  So hopefully, one or more of them will see this post and chime in, as well.