I started playing with a simple 4-4-2 formation at lvl 1 and 2, then I tried some variations (like W&N - diamond, 4-1-4-1 etc) at lvl 3. And now at lvl4, I´m still going with the 4-1-2-1-2 or 4-4-2 classic and doing well

As @July.Fourth told me and probably mentioned earlier - Play your own game! Don't make it complicated.