I took some liberty to make some edits (difficulties, wording, adding examples). I personally am going to test this approach with my players and I feel it strikes a really good balance.
Learning Through Experience
The Referee can award Advancement Points (AP) for a skill in play where he feels that a character could have learned something through experience or observation. A character can have up to three AP on any given skill. A player may improve any of his character's skills that have AP. To do so the player makes an EDU check with the following difficulties:
(Example is with a 0+ EDU modifier)
Gain a new skill at 0: Difficult (27.78% / 41.67% / 58.33%)
Increase a skill from 0 to 1: Very Difficult (8.3% / 16.67% / 27.78%)
Increase a skill from 1 to 2: Very Difficult (8.3% / 16.67% / 27.78%)
Increase a skill from 2 to 3: Formidable (0% / 2.78% / 8.3%)
Increase a skill from 3 to 4: Formidable (0% / 2.78% / 8.3%)
Increase a skill from 4 to 5: Formidable (0% / 2.78% / 8.3%)
The APs associated with the skill are applied to the roll as a DM and are removed regardless of the roll's success or failure.
Awarding AP is entirely up to the Referee which allows them to dictate the progress of Travellers (if any). The Referee might award them for completing adventures, heroic feats or time spent studying and practicing.
Examples where Referee’s might award AP:
A player is caught in the act stealing from a crime boss and his only option is to bluff his way out of it with Deception, but he’s not trained. He takes his chances and by a stroke of luck, deceives the goons and gets out. The referee is impressed with his heroic task check and awards the player with an AP for Deception, figuring he learned a thing or two.
A player is on a long-cruise and will spend many weeks in space. He brought along Programming for Dummies to work on his Computer skill. He spends 24 weeks in total studying the book, and the referee awards him an AP in Computers for what he learned.
A team of Travellers just rescued the space princess from a group of space pirates. It was a multi-week adventure to track them down, infiltrate them and fight their way out. They had to use a variety of the skills as a team to pull it off. The Referee awards one player a Gun Combat AP for all the work they did in the escape; awards another player an Investigate AP for their efforts in tracking down the pirate base and finally the final player with a Mechanics AP for the crucial repairs on their ship that enabled the escape.