One of the posters suggested that soldiers should be trained from simple peasants to elite stormtroopers or something. I don't think we should do this. Just having the ability to increase the skills of warriors legions would not be fair to the other crafts. The only suggestion that I saw that I liked was hiring helpers of other races. Dwarves are good at mining and smithcraft.
Elves are good at archery and the making of cloaks.
Well, you get the idea. With no skill the helpers will work at skill 1. The maximum is in there because helpers will never outperform the craftsman. So with no management skill your men will help you at skill level 1, even if you have hundreds of them. They only be able to help you at tasks that need skill level 1.