This rule will likely be different for each individual Eventholder, but for me it is…Do Nothing. By this I mean put yourself into a position where you have no assigned tasks during your event; delegate the key staff positions to someone other than yourself.
Why? Not to inflate your ego, but you are the central person for the event. Often you are the only person who can answer questions relating to your event. It is your vision and your design. For example, if you are acting as Magic Marshall and checking in late-comer’s magic books and there is a problem out on the field, how can you resolve the problem from the reg desk? If you are the main NPC that the players are trying to kill for the weekend, will you have to break combat to answer a question only you as Eventholder can answer?
No matter how much you prepare your staff, there will always be multiple situations you will need to deal with over the course of your event. Trust me, even if you have no assigned task for your event, you will be busy regardless. Thus it is always best to delegate key tasks to your staff.
What type of tasks should an Eventholder assign? Here is a list of positions a good Eventholder will fill with trusted people. You may find you can double up tasks onto a single person if you anticipate low need of the position (such as an NPC Boss during a tourney event) but it is good to recognize some of the key tasks involved in throwing an event.
Registration: This is the person who collects the money for your event and points people to other key personnel, such as the Magic Marshall. This position is tricky because it always lasts longer than at first is anticipated. Not all your players will show up before your start time, in fact, it is usual for players to straggle into an event over the course of the entire event. You want to be ready to take their money.
Magic Marshall: This person will check in spell books and magic items, as well as deal with certain spells that require a Magic Marshall after play begins. If you have enough personnel you can make use of two Magic Marshalls, especially during the registration part (or have one person deal with spells and another magic item check-in).
NPC Boss: Essential for a quest event, this person makes sure the monsters are set up. They make sure the NPCs know their monster stats and are in the appropriate costumes. He is also the central person to go to when NPCs have completed their last task. Often if there are multiple encounters going on at the same time, NPCs will get separated from their groups (especially if they have multiple respawns over the course of an encounter) and will need new roles for the next set of encounters. An NPC Boss gives a place where your NPCs can go to, so they are not simply standing around lost.
Set-Up: For those events where you have dungeon configurations to set-up between scenes (as seen in many dungeon events) it is wise to have someone in charge of the set changes. This will better utilize the limited time you have to change the sets by providing a go-to person that your NPCs can go to for what tasks they need to do during the set change. This type of position is very useful for any type of event wherein things change over the course of the event (like if new tourney set-ups are needed).
Food: Even if you are not throwing a feast, you still should provide drinks and some limited food (salty) for your players. This is more of a safety concern than a matter of giving free food to the players. However, the food/drinks will not get out to the playing field by itself so it is a good idea to assign someone to make sure there is enough food/drink available for the players.
Safety: This person is the one who will respond to an emergency/health issues. Even if you do not have a qualified person on your staff, there is often someone at the event who can work in this regard. Know who this person is and make them the de facto person when an emergency occurs. What you do not want to happen is a large group of people surrounding an injured person getting in the way.
As already mentioned under the Magic Marshall position, you can subdivide some of these tasks. For example, if you are running a dungeon crawl with many set changes, you can choose two people and alternate which one is in charge of which set change. So you would have Player A in charge of the first set change and then Player B do the second set change and then back to Player A, etc.
The key here is to make sure all the important tasks are covered by someone other than yourself, thus freeing you up to deal with all the problems and questions that will arise. Can you think of any other tasks should be covered?