How to defend crosses?

Tons of goals by IF/Wingers..
I trying deeper lane/man mark/OI's/tight marking, close down more, but nothing, so annoying

Some questions to ask yourself:

1. Am I playing too attacking?
2. Am I exposing my fullbacks due to not playing wingers? (and if I am, am I seeing the attacking benefits?)
3. Are my fullbacks lacking in pace / positioning and getting caught out?
4. Do my CBs have good enough anticipation, bravery, positioning and jumping?
5. Should I be adding a new squad screen view to incorporate more stats? (headers won %, mistakes leading to goals, interceptions, headers /90, etc)

Don't overcomplicate the tactics, keep it simple and focus more on individuals. If you can't bring in better players then look to cover some of your weaker areas by either protecting players (playing a high team/work rate winger in front of a weak fullback if the issue is getting double teamed down the wings, asking the fullbacks to do less if the issue is too many balls coming into the box, playing a deeper DMC to help the CBs out).

FM is a numbers game, either your tactics don't suit your players or you've just bought mentally weak players who don't have the testicular fortitude to deal with the likes of Jan Koller.