.....by being beautiful and in need of someone to help her let loose apparently

By existing, apparently.

By being the secret lovechild of Suzaku and Lelouch

By listening, allowing himself to be dragged along by her, and by being a total gentleman.

Also coming to her rescue at least once.

these are all good answers and they are all correct

the answer is to be someone Milly wants to seduce

once you are the target, she is the target. its fucked up like that

What UltraDude said

Konoka's more likely to get swept up by Milly than the other way around

by accident, and happening to be cute