if there is a lot of difference between your characters and the opponents, you do not win exp, if a character gets knocked out, he does not win exp. To win Exp you will use the multipliers, for example, if you have fewer characters than the opponent (2 vs 3) you gain a little more, if you knock out all the opponents by lust, you gain an extra for each one.
The best recipe is to have a group of girls, upload technique and charisma, the girls captured tend to have better scores than those hired (they have a lot of stamina)