Meditation helps you regenerate your Mana faster. A skill every Mage should have.
Meditation works both passively and actively. When using your skill actively the Mana that is generated is doubled.
When you wear anything heavier then Leather Armor or have anything else but a Spellbook in your hands, you wont be able to meditate or gain the benefits from having the skill.
Using Mediation actively will require you to stand completely still, any action will break it. Its a good idea to tell your friend that you are going to meditate, if hes smart he will cast an invisibility spell on you to keep you from harm.
Training meditation is easy, and usually you wouldnt even have to worry about it when training your Magery .
Each time 1 mana is regenerated Meditation has a chance to gain. Using the skill manually by activating it, will also yield a chance to increase your skill.
0 - 30 Visit any NPC mage and hand him a few coins in exchange for lessons.
30 - 120 Cast Spells.. and then some more spells, or scribe scrolls.. whatever it take for you to spend Mana points.
The Numbers Edit
Rate from Med & Int = 2 + (Meditation * 3 + Intelligence) / 40
If you have a skill of 100 or better in Meditation you get a 10% bonus, making the GM+ formula:GM Rate from Med & Int = 2 + (1.1 * (Meditation * 3 + Intelligence) / 40)