How do you troubleshoot your tactics ?

[Mulagar]

Been playing for a bit and I'm now on my 3rd season with Man Utd.
My go to tactic is 4-2-3-1 Wide. Works well for the league but cup competition has been very tricky for me.
It goes something like this (from left to right)

CF A - Neymar
IF A - Depay
AP S - Mata / Januzaj
IF A - James Rodriguez
MC BBM S - Pogba
MC BWM D - Lucas Romero
WB - Shaw
CD D - Rojo / Balanta
CD D - Phil Jones
FB Auto - Rafael
SK - De Gea

Instructions : Retain, Shorter, Pass into Space, Work Ball, Play out, Whipped, Exploit Middle, Drop Deeper, Close down More, Expressive, Lower Tempo

Do you guys notice a glaring weakness just from the basics information above ?
What do you do when you notice your tactics just aint working ?
These days I dont watch football anymore, I guess I just dont know what to look for when doing a Full / Comprehensive match view.

My team beat Chelsea 3-0 and 6-0 during league games but when I met them in champions league QF Chelsea were somehow impenetrable. Lots of attempts with no goal. Also players would often try long range shooting even with Work Ball TI. I quit the game in disgust after we were down 0-2 despite overwhelming possession and attempts.

 

[Fusershift]

Your players will be forced to pass very short with all those possesion instructions which might be the reason why they're taking so many long shots.

 

[Igneos79]

If your players are making long shots even when instructed to work ball into box, it means they had no alternative, no passing options...If you were playing agressively, the game widened them so when you tried that kind of shorter passing, they were to far away for the pass...I usually keep possession when playing less agressively, shorter with counter mentality, and retain possession with defend mentality, because the players are naturally standing deeper and narrower. With control I play direct, and with attack mentality I play go route one. I guess you might get away with shorter passing if you instructed them to play narrower with attack mentality, or retain possession with control and narrower, but it wouldn't be a sensible thing to do. With agressive mentality, it is natural to try and stretch them wide, and try to score, not only would you lower your goal chances with it, you would also create tremendous strain on your players by asking them them to run ahead of ball and try to keep it at the same time...