Before tinkering on formations , sometimes losses are caused by something not being set accordingly.

1 example, I aim to win the competition so I try to buy a good team, but Ive noticed that Ive lost matches, that I should no way lose.
A lot of friendlies but also important matches.

I came to realise that setting a good winning bonus, makes huge difference. It affects their motivation directly.
Ive won from better oponents, couple leagues up , and or with way better teams. Very often directly related to the differences in winning bonus set.

i tried it with a friend who was a couple of leagues up , with friendlies. To make a point, I didnt tell him after he had lost 6 games consequently. He was ready to go nuts hahahahaha.

I have my winning bonus set maxed out. This will give less revenue per winning match...however it will help you get further in leagues and end higher in competitions, earning more on the long run.

Offcourse formations, proper teams, and all that matter too. My point is, its an and-and situation, everything has to be set accordingly for overall best performance.

Hope this helps you.