I discovered an interesting tactic, it might not be the best but it is definitely interesting, and if you have good defenders you might not concede at all, i didn't have time to test it with more teams etc, but i had great results with it.
I discovered it by trying to reduce the amount of goals I was conceding from corners after I was kicked out of the cup and UCL, from the 4 goals that I conceded 3 were from corners :<. I saw that if I keep more players forward the AI will try to keep 1 more than me as well.
To shorten it up: 2 players marking the posts, but important MUSTN'T
be the full backs, depending on my tactic I have either the wingers or central midfielders. Centre-backs are set to mark tall players, the full backs to mark player/mark small player and a defensive midfielder, if you have a good one put it to edge of area, or if you don't have a good 1 put a player to close down corner. All the other players, and if you have quick wingers here they are good, keep them forward, will result in many counter-attacks and many goals, while drastically reducing the ones you concede.
Test it as well and come with some feedback, you will see why it is so interesting after the first 2 corners, and why it always keeps you with your heart close to exploding