The best tactics to use, when playing with a 3-4-3 formations, is having every little bar, three clicks from the end.

So on the tactics screen, where you select what wing to play, how far up your defence push and such, put all of the little bars, three clicks from the end of the line, then go to the training screen and prees 'A' and it will come up with a message saying you don't want your assisstant coach to do it, say you want to, and the tactcs trained will copy your your tactics from earlier on.

The best formation for this game is 3-4-3, it won me the UEFA cup with Celtic, conceding 8 goals in all competitions, and won me the Champions League with clubs such as: Ajax, Liverpool and CP Sporting.