I see a lot of GM horror stories that essentially amount to “The game isn’t going the way I’d planned! Now I’m on fire, and my pet Chihuahua is wearing a fake mustache!”. Well, I actually hear a lot of the first frantic exclamation, and very little of the second, but it’s been a long week and I’m taking some liberties from reality. Frequently, the way to get what you want as a GM is to give what your players want, and use it to shape their interests toward what you will do.First off, recognize that players are independent, often opinionated, people with their own ability to make judgments and decisions. This advice is intended to help you make a game match your own interests without losing players and making them hate the game, and to a certain extent you have to know the limits of how far you can go with respect to bring your players into line with what you want a game to be. For instance, I love the concept and setting of Eclipse Phase, but my players look at games with a strong eye toward the mechanics, and they aren’t as enthralled with the idea of space kinda-humans as I am, which only counts double against the game’s weak mechanics.
Start by figuring out your players’ preferences. If they like mechanics, give them a system that rewards that; if they like narrative you can use a system that focuses more on storytelling and a rules-light environment. Don’t try to force them into a certain genre, and remember that not all settings immediately work for roleplaying with every group; if you’ve got a group of players who all want to be heroes all the time, gritty cyberpunk will either challenge them or make them quit. Know which response your players will have- if they expressly want to be knights in shining armor you may be better off placing them in a morally unambiguous setting or game. Feel free to ask, survey, and generally annoy your players about the things that they want to see in the game so that you can better respond to their desires and goals, rather than feeling like you don’t care about them; having players enjoy your game is often more rewarding than having a game that you enjoy but other people just show up to out of obligation or politeness.
Next, figure out what you want. Some of the campaigns I’ve enjoyed the most have been unexpected, and some of the campaigns I hated the most were ones that I went into with really high expectations. “Know yourself” is a pithy saying; figure out what’s going to go on and set up your game so that you can create a positive environment. If you hate players missing games or not paying attention, ask players to either step up their game or not come at all (of course, it’s a good idea to make exceptions for players missing games because of good reasons, as dropping a player because they get sick is not only cruel, but also really bad for everyone else’s morale). You should define the criteria that you think would make you enjoy the game, and be sure to be flexible. Just make sure that if you adjust your final goal on the fly that you aren’t jerking players around too much, and tell them when you decide to change the tone or feel of the game. Remember that you are a part of the group as well, and you should feel free to communicate your needs and desires to your players.
Finally, once this is in play, you can begin customizing your experience. If you want to move the setting darker, have events occur that make the world more dangerous or expose hidden treachery. Add new rules or override old rules as needed to make the game more interesting so long as the players are fine with it. For instance, I play Shadowrun without caring about Essence except as it pertains to Magic or Social Limits, because I like the idea of letting my players continue improving their street samurai in my low-level campaign, and they’ll never get the money for alphaware, much less deltaware.
An important thing to tailoring your experience is to think like a game designer. If you want a more fast-paced d20 campaign, boost damage output and remove Damage Reduction from the game, which will make battles go a lot quicker. Think about the effects of the things you change on the setting; the aforementioned damage boost either makes the game feel a lot deadlier or reinforces the power of the players, depending on how you curve the balance. Look for things that you know are easy to change and can really shift the mood; L5R, for instance, suggests multiplying the health values for a more fantastical and less realistic campaign. Sometimes you need to add new elements to the game, such as armor losing effectiveness over time, to balance the effects of a player who has become too powerful, but be sure to do this in a manner that adds to the drama, rather than merely punishes an effective player. Use it to encourage flexibility and creativity, break out of ruts, and move toward a desired vision of the game, rather than simply making random and arbitrary changes.
In short, if you want a game that works for everyone, know what your players want, know what you want, and make the appropriate decisions and changes to the plot, setting, and mechanics to bring your game in line with your vision.