1. How do individuals join a guild?
They have to be invited, but they also can ask if they can be invited.
2. How does an avatar upgrade their fighting capabilities?
They must earn it. By doing quest and accomplishments they can be trained.
3. Can an avatar play with a partner avatar?
That is on a personal level. If two avatar agree to play together then they can but here is no official alliance. Most of the game is played player versus player.


http://us.blizzard.com/en-us/games/wow/

Overall I liked the forum. I had difficulty at first because I had no past experience with one but I am very glad that I learned how to do it. I Think its a great way to host a class. Easy and self explanatory.