The idea that someone must gain experience in the form of saving towns, killing creatures and saving old ladies from burning buildings, just to turn that experience into the ability to build bombs, read the stars or how to fix up a friends wounds seems silly to me. I suggest that the current achievement points = skill points be dropped. Achievement points should still exist, but just to convert into perks, buy off flaws, and to get achievement benefits. Initial skills are determined by the method in GW5. Then any skill can be taught by someone who is 3 ranks above the student (except ranks 10 and 11 who can learn from a rank 12). The student must make a complex INT feat check, once per month, with the following penalties:

Rank	Penalty
1 - 2	0
3 - 4	+1
5 - 6	+2
7 - 8	+3
9 - 10	+4
11 - 12	+5

A new Perk (described below) reduces this as does the hero's INT resistance modifier and the teacher's skill (q.v. teach skill). Learning a new rank takes one month/rank of game time. And only 3 skills can be learned simultaneously. 

Fast Learner
Cost 10/18, INT, Conscious
A hero with this perk has a better time learning new skills. He gains a -1 step bonus to any attempts at learning a skill (-2 for the 18 point perk). And the time needed to learn a skill is reduced by: 1/2 for ranks 1-6, 1/4 for ranks 7-10, and 1/8 for ranks 11 and 12.

Note to all GMs who want to use this, remember that you control the teachers here. This is not Star*Drive with billions and billions of people in a high tech society - it a broken world where some skills are all but forgotten (ie you might restrict some skills to rank 6 or 8). You may want to limit "adventuring" while they are learning as well, especially if in a school.

Example:
Fred is learning the way of tracking from George. As Fred already has Investigate- tracking 2 and wants to learn as much as possible from George (rank 10), that means that Fred needs to spend 8 months under George's tutelage. His player must make 8 successes with a INT feat complex check. If he gets a critical failure, he learns nothing, even if it was during the last month. If he gets a 3rd failure, he learns up to the previous month's "rank" (e.g. he gets the 3rd failure in month 5, he gains a current rank of 6). In cases of learning a broad skill, it takes 1/4 of a month for every specialty skill under that broad skill, this includes any new skills the GM creates. The GM might also reduce this number if certain skills are not in his campaign.