Rules for effective gamemastering
The Viking Hat Way
1. Bring snacks.
2. The dice are always right.
3. I master the game, the game does not master me.
4. Momentum over perfection.
5. The game must go on!
You must bring snacks because gaming is social activity. In every culture and religion worldwide, sharing food is how people bond. You will observe that people who do not bring snacks tend not to contribute in other ways - especially if they never bring, but always take. As with snacks, so with everything else.
The dice are always right because nobody likes boxed text and being railroaded, and gaming like life is meaningless without the risk of failure and death. The dice enhance the creativity of player and gamemaster both.
I master the game, the game does not master me because no collection of rules can ever anticipate everything that might happen at the game table, and the ideas and whims of players and gamemaster. In other words: "I am the GM, I wear the Viking Hat!"
Momentum over perfection means that it is better to keep things moving than to get things perfect. Generally speaking the randomness of your decisions will be much smaller than the randomness of the dice, so make a quick ruling or judgement and move on. Sooner burn all your game books than bore anyone at the game table by spending the session looking up charts.
The game must go on! means simply that. Do not let the lateness, absence, indecisiveness or emotional infarct of any individual player stop things from happening.
There are of course many other ways to play, all of them wrong.