Found this training idea online today when looking for more info on Stoyko exercises. A Dutch chess trainer going by the name of Phaedrus likes to do a Stoyko exercise with a position, and then do the following:
Setup the diagram position in Fritz or any other chess engine you have. Fritz has the option to chose a level. For starters chose a level with a fixed depth. Start with 1 ply, or if this is not challenging enough for you, with 3 ply, and try to win the position against Fritz. If you do, move up a level and play out the position with the engine set to 3 ply. Than 5 ply, and so on until you can't beat the machine anymore. As soon as you stop winning, analyze the games. What went wrong, and where. As soon as you think you know how to do it better, try again at the same level. At one time or another, no matter what you do, you will not win anymore. This is the time to stop and move on to another position.