It would be redundant to list the obvious rules of conduct that are listed on so many sites and referred in other locations of ours. Instead, we'll offer some advice on hosting since not as many sites discuss it in depth. The reason you don't find much advise on hosting is because it is a subjective matter. The following only represents ChrisP's methods and is not intended to be gospel.
1) Greet people as they come in. Show others recognition and respect and they will likely return the favor.
2) Use a title that your clan mates and friends will recognize.
3) If you're getting alot of complaints of lag, ask who else has a good connection and see if they will host instead. Note: A person who is getting lag in your game will probably lag you as well if they host.
4) Give annoying people a hint of their impending boot before you do it. Maybe someone will learn from their mistakes that way. Booting people is serious business, but don't hesitate to do it if you sense your friends are having a bad time because of some jerk.
5) Always give a 5, 4, 3, 2, 1 countdown before starting, even in Myth2. This allows people in the middle of typing a sentence the chance to finish it and helps to ensure everyone is really ready. My rule is to count faster if there's not alot of people in the room and slower if there is a lot going on.
6) Always give people the chance to check out the post game stats and discuss the game. When restarting, type "RSing" and wait a few seconds (for the same reason as #5)
7) Try to strike the right balance of chat and play in your hosts. Generally the more crowded a room gets with people who know each other, the more they will want to chat. Be aware of quiet strangers that entering your game and for their sake, don't delay the game too long even if everyone else is rambling away. Recently, I entered a room hosted by one of the more prominent unranked clans. Being the outsider, I waited patiently for 10 to 15 minutes as they just chatted. As it turned out, they were waiting around for a planned clan meeting to commence. With no intention of playing, they didn't bother telling me until it was time to ask me to leave. This kind of inconsideration makes the community lose respect for a clan very quickly.
8) The biggest headache in hosting is dealing with many players who all want to play their favorite game. No matter how insistent people are being, remember you're the host, and thus, the boss. Tell people you will get to their choice soon and if they must have it immediately, let them go elsewhere. Try to reasonably accomodate everyone, listen to what people want to play and switch maps/games frequently. Unless I know everyone wants to play the same game again, I switch every game.
9) Try to stick to maps you know everyone has. Politely recommend to the inevitable one person who lacks the map everyone else wants to play, to download that map for future play. My exception to this rule is the Unity2.gor, if you don't have that one,...cya...
10) Another dilemma in big games is overcrowding. Once the room reaches 10 players, I use our informal password: polly. This helps to insure that the last few slots in a room are reserved for clan members and friends only.
11) Don't forget that you owe as much to the players joining your game as they do to you for hosting. Always say thank you to everyone after you close the game.