Advancement

Advancement is what makes your character more powerful and receive more abilities. There are two forms of level advancement. Adventuring level advancement, and guild level advancement.

Adventuring level advancement can be done in any adventuring guild. Adv Guilds(Adventuring Guilds for short) can be found in just about every city. When you are in a city just type 'map' and check the map carefully to find one. In the Adv there will be a room with a few commands, 'advance', 'cost', and 'list'. Advance is the command to increase your level by 1, given you have enough experience (we'll get to what this is in a moment). Cost will tell you how much exp (experience for short you will need for the next level). And list tells you the costs for all the levels 1 - 100 in the game.
Guild Level advancement allows you to improve the stats (strength, constitution, wisdom,etc) of your character, as well permit you to study more spells and/or train more skills(we'll discuss more about these in a moment too).
Important Note
You can only advance in your guild as long as you have free adventuring levels.
Example - Bob has 5 adventuring levels, but he is only level 1 in his guild. Now he can advance up to level 5 in his guild but no further, as he has no more free adventuring levels.

You will have to go back to your guild in order to advance in it. Also, Guild level advancement requires exp as well.

Decide how much your level costs for both your Life Level (aka Adventurer Guild Level) and your guild level will cost. Figure out how you're going to spend your experience points in advance. Generally, it's a good idea to go to the adventurer's Guild (using the exit labeled "adv" or "adv-guild") and advance your Life Level in the Advancement Room, then return to your primary guild (using a transport room, nearby the Adventurer's Guild) which will take you back to your guild area. Find the guild advancement room, and go up a few levels. Advancing three levels in each is probably a good idea.