Lessons are the easiest way to progress in a given skill. You can learn as many lessons as you have lesson credits for. Lesson credits are built up over time as you grow older in the land. Unless your character is in a "non-lessongain" state (e..g. in a protected safe location) every TWENTY minutes you will accumulate a lesson credit. You do not need to do anything special, nor pay anything for the privilege: it happens as a result of just living your Avalon life. This lesson credit can be used any time you like to LEARN from another player, NPC or CCC and thereby increase whichever skill you choose to learn. Lesson credits stack so you do not need to use them immediately.
Check out HELP SKILLS for command and syntax details for LEARN, TEACH, SKILLS and other important commands for learning and browsing skills and their abilities lists.
It is very important you are aware of the factors that will prevent your lessons from accumulating. There are two main reasons: the location you are in and your character being in a "non-lessongain" state.
Locations in which you will not gain lessons can be checked out by typing SURVEY. You will see the text "and thus affords no lesson gain" in the survey response and this should tell you to move elsewhere. The locations in which lessons do not accumulate are those of protected or sundered-from-Avalon type: the Pool of Life, the bulletin board, the Underworld, highly marked holy locations (e..g.. possible sanctuaries), rooms with safeguard shielding, enforced peace, or special protections (e..g. treasure chambers, commodity sheds, shop stockrooms, barracks interiors, the ethereal winds, etc) and locations in which globe-stave wreathe or conquistador is active. The principle is simply that standing around in an invulnerable position is not gaining "experience" of the world; hence no lesson gain.
Your character is normally in a lesson gaining state. To be in a "non-lessongain" state, you will need to be: idling (i..e. more than an hour without any activity), in poltergeist or ghost form under half mana, existing as a stone statue, having no game-playing credits or active subscription, extreme hunger (starving to death; ill through lack of food) and/or sleep deprived. Type STATUS to see your levels of hunger and fatigue. Idling is not penalised if you are still on the JUNIORS list.
Type LESSONS to see how many lessons you have gathered and any learning enhancements in effect.
It is possible to acquire lessons via procurement to speed the pace of learning and ability acquisition. Procurement is explained in HELP PROCURE. It uses "real world" currency or the gift card from the Curiosity Shops detailed in HELP SHOPPING.
Lesson and lesson-potential info is shown when you type STATUS in among much other pertinent character attributes. Use LESSONS on its own to see only how much you can learn and how suitable your current location is for taking lessons.