SM Experience Points

Learning On the Job
Characters start the game with skill levels compiled in the generation/development stage. In play, like in life, the learning process does not stop when the formal education is over. It is an ongoing process and the more a skill is exercised, the stronger it becomes.

Each specific use of a skill will gain "experience points" (EPs). These EPs are collected until they equal the number of skill points. Then the skill itself gains a permanent, additional point. Leftover EPs roll over into the next pool. This makes improving skills especially easy in the beginning and especially difficult at advanced levels.

The Curricula of Life
EP may be earned on successful attempts at tasks with DoDs that are 50%+ of the associated skill level. A task that is too simple will render no usable experience. For Bob the Basket Weaver, basket DoDs of less than 20 will grant no EP.

The number of EP earned is based on the DoD accomplished. The EP is 10% of the DoD, rounded up to the nearest whole number.

Failed attempts will garner full EP if the character takes an appropriate amount of time after the failure to analyze why the attempt failed. The time required is variable based on task and circumstance. Smart people often learn more from failures and mistakes than successes, and the Ref is encouraged to take that into account. Failure under duress may preclude the opportunity for task forensics.

Phenomenally creative applications may earn more, even up to twice the DoD. I would recommend reserving this bonus option for the absolute masterpieces of player ingenuity. A little cleverness keeps the bonus at one or two extra points. If you'll be talking about it for weeks to come, only then should the Ref consider a more generous bonus.

Student Effort
During the course of the game, it is the responsibility of the player to record the use of a skill. Increases in skill points (after accumulating enough EPs) are made during the gaming session.

These epiphanies of experience do not typically wait for uncomplicated times to enlighten. However, if it bogs down play too much, the Ref may choose to calculate the growth sessions after each game.

Self-Improvement Tips
Like skills, some particularly good use of a trait can garner some EPs for it. Most of the time, this will be limited to direct challenges, not the use of something as a modifier for something else.

Again, key or clever uses can go around that, but keep it rare. Throwing out EP like confetti cheapens the value of experience and spoils the PCs. Pretty soon everybody has legendary characters, nothing is a challenge, entropy is accelerated, and the Universe comes crashing in on itself because all purpose is lost from existence. Just be fair...

Training within the Campaign Narrative
Certain campaigns may include a period of education, training or other conditioning and growth possibilities. This might include something like active-duty military characters who finish a sub-campaign or scenario, and are sent for training and qualification at some specialist school.

If the narrative calls for it, there are few limits on the number of additional skills added by this method, though skill levels tend to reflect that they're "just out of school" (often between 8-18 in contemporary settings).