Before the Game
Everyone approaches game mastering differently—some with intensive preparation, others with a sticky note and a prayer. Yet, regardless of your personal style, there are a few matters every GM should consider in advance to save time at the table.
If you’re running a published adventure, be sure to read it beforehand so that you know what you’re in for and can adequately prepare your notes and foreshadow upcoming events. (If short on time, you can sometimes read just the first few encounters—enough to keep several steps ahead of the players.) If you’re creating your own adventure, make sure you have enough written down to feel comfortable. Gather any props you need, such as miniatures and handouts, in addition to the usual dice, pencils, tactical maps, and so forth. Consider helping your players prep for the game as well, such as by resolving character story issues that don’t involve the group as a whole (perhaps even via one-on-one side quests), answering questions, and helping them level up their characters.
It’s also important to consider real-world logistics. Make sure that all the players can make it to the game; if someone can’t, consider whether it’s still worth running the game, and if so, what happens to that person’s character. Do you or another player play him? Does he continue to gain wealth and experience, or will he fall behind the rest of the group? Also, consider matters such as food, children, pets, and other factors, and have a plan to handle any concerns that might arise.