How to deal with frustration?

Interrupt the cycle

Interrupt the cycle by letting him/her wait a few moments while breathing deeply in and out. This can be enough to regather the required focus. If it still doesn't work out then go on with the next part of the training for the time being. The thoughts can be focuses on something else and the player has the chance to cool down.

Another possibility is to interrupt the training with an exercise the player loves to perform (doing head-shots, being a goalkeeper, taking shots, doing volleys, ...). When this is combined with a certain game element the negative feelings usually disappear in no time.

When the player tries again later during the session it suddenly happens to work out well. Or not. Sometimes it just will not happen for that day and then it's better to skip the move or drill completely for that session. After a good night sleep where the new information has been processed the player often experiences the move or drill as being easier the next time it is being practised.

Another good strategy to consider when a player experiences some difficulties to get a new move under his belt is to break it up in several parts. By isolating the problem it can be overcome sooner. Or repeat the basic drills if the move is based on it.

It is important to get the correct procedure in memory in the first place. The speed of execution will improve later on.

That 'one 'move

But there certainly will be moves or drills that just won't work out for a certain player.

Because nobody likes to fail, let alone repeatedly, it's useless to keep pushing the drill since it could change a positive attitude in an instant which has a direct impact for the remainder of the training. Worse, when this demon is coming back time after time, the player could start to have doubts which could bring down the self-confidence of the player. Leave the move from the schedule for the coming months. By practising other moves or drills and gaining the extra coordination skills as a result it could work out later on.

One can count on the fact that there always will be that one move that will raise the hair on the arms of a player when it is even mentioned. Don't waste your time any longer and drop it permanently. There are hundreds of moves and drills to practise.

That one move won't make any difference and it doesn't make him/her a worse player compared to someone who masters it. That player will have his/her own demons.

At the end the purpose is to let a player make general progression while enjoying the game. Self-confidence is gained by mastering a whole set of moves, and failing a few won't hold one back.