I've taken a bit more of an urgent interest in the stat and skill increases lately too, as the race my players are playing start with fairly low physical stats (except dex) and begin aging a term earlier (equiv) than humans.
So, suddenly, after the FIRST round of aging rolls during the course of the campaign, the characters are suddenly aware and on edge over their mortality. Rightly so, in character at least. Out of character, they have the option to play their own offspring - but players do get attached to their characters. Nevermind the dangers of star travel, unexplored space, political upheavals and adversaries on their home planet, etc. Aging is apparently their new enemy #1.
I've kinda settled on something that approximates char-gen rates of stat and skill increases, though a little on the forgiving/generous side of things. Each year of training earns a base 7+ to increase a stat or skill, with the level of the bonus being a negative modifier to the roll (NOTE: I am using MegaTraveller's rules for stat bonuses ... ie. divide by 5 round down - but this should work for MGT as well - just don't give a "bonus" for negative modifiers - ie,. really, really low stats).
So, to raise a skill from a 2 to a 3, the character would have to a) declare he's working on that skill, b) have the opportunity available to train, experience, study, hone their abilities, and c) at the end of one year, roll a 9+ (7+ with the penalty of already having the skill to level 2).
To raise a stat from say 9 to 10, as above, but the target number would be 8+ (7+ with the penalty for having a stat with a benefit of a +1 modifier)
Only really lucky PC's will raise more than a one already high stat or skill in a 4 year period and characters attempting to stave off aging have a fighting chance, if they devote all their time to maintaining their physical status, at least until they hit that nasty wall of stats dropping 2 per missed roll - which also comes earlier for the players in my campaign, and Anagathics aren't an option - max TL available is about 12, excedingly rare, and the only known natural anagathics discovered so far only work on humans.
Throw on your own skill level limits or what have you, and it can approximate the 'progress' of character gen if played right.