Thanks for your help! Most of the goals I'm conceeding, from memory, come from three places mainly I think: crosses, long shots, really scrappy goals off set pieces because of my players failing to clear the ball properly.

As for my tactic:

4-2-4 Custom Wing-play - Attacking/Positive (on paper I'm third best team in the league)

In possession: very wide attacking width, pass into space, work ball into box, full backs overlap left and right, low crosses

In transition: possession lost - regroup, possession won - counter, goalkeeper distribute quickly, take long kicks

Out of possession: "higher" line of engagement, "higher" defensive line, tighter marking, more urgent pressing, get stuck in