Join Date: Jan 2007
Location: Outside Madison Wisconsin
I've found that losing can be a good teacher, but in learning, the student needs to have a chance to win in order to keep going.
From my own experience, the best method is to play at approximately 10% above the student's level. That way they'll have to improve a bit to win. If they win, then they've earned it.
The bad thing is, I see guys at the Game stores play new guys with army lists that are really far superior to what the new guy has. Nuking the new guy over and over really doesn't teach them anything. Even if you simply show them how to min-max their lists, if they don't get a "cookie" once in a while, they'll stop playing (which is what drives a lot of folks away from the game).
In RPG terms, they have something called "Social Contract". This is where the players come to an agreement before playing as far as their expectations. In Warhammer terms, this would likely be something like "Friendly" or "Competitive".
If you are an experienced player, and you are playing an unknown, possibly new player, then I would recommend talking with them, getting an idea of their skill set and adjusting your plan of attack accordingly. If they are new, then maybe it's a good time to goof off a little, try some dumb ideas, and don't necessarily gut the poor fool by deep striking those termies right behind his elemental and bodyguard. Give em a break. If you win, cool. If the newbie wins...hey! Good for them! Both had fun.
If you find you are up against somebody your own caliber, by all means, rock their world.
My recommendation though, for pretty much everyone who plays any kind of game, is to talk about the game a bit in advance and see what the opponent is ready for. Although it's a competitive game, it's also a competitive game and fun for both players should be a priority.
I think as long as an attempt is made to ensure both players have fun, there should be no reason to ever feel bad about winning.