Professor Mario:
I learned this method from a couple of different sources but the first and most influential source is Super Mario Bros. That's right the video game. In Mario Bros you press start and the game just starts. No tutorial, no pop up on screen telling you what to do. Eventually you look at the plumber sitting there and you push the D-Pad. Hey look he moved! Hit the button - hey cool he jumped! So eventually you go right. There's some blocks and a turtle. What do you do? Well you know you can jump so you jump over him. Maybe you land on him. Right by the turtle are some blocks. When you go to jump over or on the turtle you hit a block. Hey you just learned you can smash blocks! Later you are standing on a pipe and a bullet bill is coming for you, you hit down to duck - wow you just entered the pipe! And so on. What the game does brilliantly is show you how to play by introducing you to each game mechanic one little bit at a time. That's the method I like to use for RPGs. The place I've seen this done really well over the years is in the Dungeons and Dragons intro boxed sets. The best one being the Dungeons & Dragons Adventure Game: The Adventure Begins Here! for 3.0 D&D. It shows you each sub-system of D&D one step at a time.
My method of teaching a game step by step:
Character Gen:
I always make characters with the players. I don't like pre-gens and the only time I will have the players grab a pre-gen and start teaching right away is when it's a single session public play con-style game. Even then where possible I like to have players make characters or at least make some of the character choices.
While making characters I won't explain much. I have a house rule in every game I run called lateral reincarnation (term stolen from +Robin Laws's Feng Shui). At any point up until the first level/tier/rank players can change anything they want about their characters. This makes sure players play characters they like and doesn't punish them for bad choices during character generation due to inexperience. I generally just tell players to pick stuff that looks cool to them and not really worry about how things work.
While making characters I won't explain much. I have a house rule in every game I run called lateral reincarnation (term stolen from +Robin Laws's Feng Shui). At any point up until the first level/tier/rank players can change anything they want about their characters. This makes sure players play characters they like and doesn't punish them for bad choices during character generation due to inexperience. I generally just tell players to pick stuff that looks cool to them and not really worry about how things work.
A basic check:
I like to start the first game, first session in media res, right in the middle of the action. You want to catch people right away. I will describe the situation and call for a very basic check. Often this is a perception or spot check. Something to see if the players notice something. I will explain the mechanic step by step. Look at your skills, find the number for X, you will be rolling a die and adding your result etc.
A complex challenge:
Next I like to see that everyone gets the basic dice system. I will create a complex challenge. A skill challenge in D&D 4e, a five step progress tracker in Warhammer 3e, an extended action in other games. Whatever it's called, this is something that makes the players each have to make multiple checks. It will be based on that first basic check and it will test to see if everyone gets the basic system. Say the first check was to know if the group is being followed and is passed. Well now the group could set up an ambush, or try to flee, or track down who is following them, etc. Once it seems like everyone at the table gets the basic check system it's time to mix things up...Dramatic interruption:
Roll for initiative! Or hand out cards or whatever system this game uses. Teach the system, explain how it works, explain rounds, and turn order. I don't usually bother to explain movement until the first person moves, or holding actions unless someone asks if they can hold. I do want everyone to understand how the game is going to flow and when they can be expected to be called on to do something.
Simple combat:
Run a really simple combat. Try to set it up so that there isn't really room to move around, a very small room or an ambush. Try to make it so that only hand to hand or melee attacks really work so you can focus on that subsystem. If you can, limit casting to touch spells for example. Have at least one bad guy live long enough to hit back so that the players can see how defense works.
Complex combat:
After the first fight set up a situation for a longer fight. In this one you want to see ranged combat. You want to see spell casting. You want people to move. If there are terrain rules introduce them. If there's cover, use it. You want to show off the wide variety of combat options.
You are going to repeat this one a few times, one for each sub system of the combat rules. Do a fight where there is high ground and show the players how they get +1 for using it. Do a fight on a bridge and showcase the pushing and falling rules. Run one with a hazard, spikes, pits etc. You want to hurt the PCs at some point so you can show them the rest and healing rules.
Dungeons are perfect for this as you just add something new in each room. Room one is 10x10 and there's an Orc and he's guarding a pie. Room two is 30x10 and there are some Gnoll Archers behind a make shift barrier at the long end. Room three has a spiked pit trap in the middle of the room and a couple kobolds luring the group on, etc.
Don't forget NPC interaction:
In the middle of these combats add in NPC interaction. Have a bad guy live and let the PCs question them. Have one of the fights involve a 3rd party. Have someone to be rescued. Have someone that needs to be escorted. Make sure you still tell your story and make the characters seem real. Just because you are teaching a game you don't want to forget to make it a true role playing experience.
Social encounters:
If the system has rules for social encounters highlight them now. If there are no specific social rules, show off how you can use skills to get things done instead of just bashing in doors and being murder hobos. I usually like to do this as the final thing leading up to the final battle. Maybe the group just defeated the Orc boss only to find out he's just a minor lieutenant, they need to question the boss to find out where the big boss is. Maybe the group has to meet with the King and explain how his court is corrupted. Perhaps the group needs to convince the town guard to move on the kobold camp while they sneak in to take out the Dragonlord. The climax:
Put everything together. A bunch of investigations and checks lead the group to the main climax (pretty much always a big boss fight). You want to show off all the neat things. Interesting terrain, working together, movement, line of sight etc.
You want to mix the three main systems here. You want a social combat - perhaps the encounter starts with the Big Bad making a monolog and the party has a chance to interject and affect morale. Perhaps there's a third party that could side with the good guys or the bad guys before the fight starts. Something that lets you use those social skills even while in the middle of the big fight.
In the middle of the fight something can happen that brings skill use into play. Picture a combat where the group is on one side of a chasm fighting the big bosses minions while he stands on the other side taunting and egging his troops on and sending reinforcements across the bridge. As the players reach the bridge he pulls a lever and it collapses. Now the group has to use their skills to go across (build a new bridge, jump, set up a rope system, etc) as well as continue to battle minions. This often comes up in Fantasy games with traps or mechanisms for thieves to play with. The thing is you want to show off that skills aren't just for non-combat.
Eventually though you get to a knock down fight. Hopefully your players have saved up their big spells and can really show off their abilities here. At this point they should all know the game and be able to shine so let them. If they crit your dragon on round 1 and kill it, good for them!
Final thoughts:
So that's my method of teaching a group a new game. Jump right in and start playing. Don't explain everything ahead of time. When you do start, start small. Simple skill checks to start. Then build on that. More checks, initiative, combat, etc. Try to teach one sub-system at a time. Don't forget roleplaying and NPCs and show off social combat and the fact skills aren't just for non-combat situations. Showcase all of this in a really epic final battle.
What's the method you have found works best for your group when teaching them something new?
