I stole this from an endgame book, I'm sorry I don't remember which one. The idea is to give students a roadmap for how to win a simple minor piece endgame when they're up a pawn. Obviously, this is not so simple, and so your objective is not that they win 100% of the time, or even 75% or any particular % of the time, but more that they have an idea of the method and get some practice at it.
I start by showing them a position
having a student tell me the material, and asking who thinks they could win this as white. (it doesn't matter what the answer is). I then ask who can explain to me what the plan is.
The plan is this:
1. Centralize the king (I explain that you activate pieces in the endgame in the order of their power, i.e. queen first, then rook, the king is worth 4, so king next, then bishops and knights, and generally only after these pieces are activated do you start pushing the pawns.)
2. Activate the knight
3. Make a passed pawn by pushing the pawns on the side you have a majority.
4. Once you've done that, the side with the extra pawn usually wins by some combination of:
a) pushing the passed pawn and invading with the king
b) trading knights
c) sacrificing the passed pawn to win the kingside pawns.
Make sure this is written on the board so students can refer to it later while they are playing.
I then ask for a volunteer to start white out by doing #1, centralizing the king. I move for black, and we play through the following moves:
1.Kf1 Ke7
2.Ke2 Kd6
3.Kd3 Kc5
I then ask for another volunteer to take over and activate the knight:
4.Nc2 Nd5
I ask what this threatens (Nf4+ winning a pawn) and how white can stop this:
5.g3 a5
Here I ask which pawn to push first, and if they don't know, remind them of the general rule that you push the potential passed pawn first, in this case the b pawn:
6.b3 f5
7.a3 g6
8.b4+ axb4
9.axb4+
At this point, you've completed step three, and I explain that you now try to advanced the pawn and be on the lookout for tactics that allow you to sneak in with your pieces, or trade knights. In general, you calculate as much as you can. Depending on the level of the class, I go faster or slower through the rest of the game: the exact moves don't matter as much as the kids grasping the basic plan in the beginning. You won't be able to teach technique and endgame control in one lecture-lesson, so don't try too hard.
9....Kd6 [9...Nxb4+ This is a nice example of how white wins fairly easily if black allows the knights to be traded. 10.Nxb4 Kxb4 11.Kd4 Kb3 12.f4 Kc2 13.Ke5 Kd3 14.Kf6 Ke3 15.Kg7 Kf3 16.Kxh7 Kg2 17.Kxg6 Kxh2 18.Kxf5 Kxg3 19.Kg5]
10.Kd4 Nc7
11.f4 Nb5+
12.Kc4 Nc7
13.Ne3 [also good is 13.b5 Nxb5 14.Kxb5 Kd5 15.Ne1 Ke4]
13...Kc6
14.Kd4 Kd6
15.Nc4+ Kc6 [15...Ke6 16.Kc5 (16.Ne5 Kd6 17.Nf7+ Ke7 18.Ng5 h6 19.Nf3 Kf6 20.Kc5) ]
16.Ke5 Kb5
17.Ne3 Na6 [17...Kxb4 18.Nd5+]
18.Nd5 Kc4
19.Nf6 h5
20.Nd5 Nb8
21.Ne7 Kxb4
22.Nxg6
At this point, I reset the position and ask a student to repeat the general plan. Then students choose a partner, set up the position on their own boards, and practice playing the position as white and as black. Ideally, they should play twice, once with each color, and should have 10-15 minutes per side, although you can do it with 5 minutes each if you are pressed for time. Do remind them that playing an endgame with 5 minutes is not at all the same as playing a whole game with 5 minutes, and they should play slowly and thoughtfully as the position is tricky.
the next day....
I follow that lesson with its sister position:
which you will notice is exactly the same, but with bishops instead of knights. I ask students again how many think they would win the position, and hopefully a few more students raise their hands than last time.
I then ask what the basic plan is, and of course its essentially the same:
1. Centralize the king
2. Activate the bishop
3. Make a passed pawn by pushing the pawns on the side you have a majority.
4. Once you've done that, the side with the extra pawn usually wins by some combination of:
a) pushing the passed pawn and invading with the king
b) trading bishops
c) sacrificing the passed pawn to win the kingside pawns.
I again show students a model game; you can also have them play first and show them the game afterwards, but I find with difficult lessons like this, many classes benefit from as much teacher-modeling as possible before they do it themselves. They play much better and are more likely to be successful if they see exactly how you do it first.
I ask for a volunteer to help me do step 1:
1.Kf1 Kf8
2.Ke2 Ke7
3.Kd3 Kd7
4.Kc4 Kc6
then a new volunteer for step 2:
5.Bc3 g6
and again a different student for step 3:
6.b4 Bb6 7.f3 Bc7 8.a4 Bb6
9.Bd4 Bc7
10.b5+ axb5+
11.axb5+ Kb7
and again, don't get too worried about covering every detail of the rest: like every endgame it gets a little messy and there are many possibilities for each side. What's below are just examples!
12.Kd5 Bb8 [12...Bf4 13.Be5 Be3 14.Kd6 Kb6 15.Ke7]
13.Bf2 [also good are 13.b6 Bg3; and 13.Be5 Ba7 14.Kd6 Bb8+ 15.Kd5 Ba7, which at first looks like repetition, but white invades after 16. Bg7 h5 17. Ke5]
13...Bc7
14.g3 h5
15.h4 Bb8
16.b6 Kc8
17.Kc6 Be5
18.b7+ Kb8
19.f4 Bf6
20.Ba7+ Kxa7
21.Kc7 Bd8+
22.Kc8
Now again, return to the original position, have a student repeat the basic plan, and send the class off to practice. Circulate and watch: the most important thing is to catch players who aren't following the basic plan. Don't worry too much about showing kids every forced win that they miss: it's a difficult position and you don't want to undermine their confidence. Keep in mind that your goal here is to give students a basic plan to follow, not to police their endgame technique.