How do I build up points for a new position ?

I have been training my players constantly but none seem to be getting any of the 50 points needed to gain a new position.
Is there something I am missing ?

You have to click on the '+' sign where it says that your player doesn't have a special ability, choose a special ability and click on start. Then you have to allocate your skill points to that instead of allocating them to attack, defence or physical & mental.

None of their skills will get better, you have to use all the skill points into learning the special ability or new role