*Note- Mill is usually a sub par strategy to win games. While you may steal some games from people, it is highly unlikely to do well in a tournament . I have built these before*
Well first suggestion I would say is to add Dark Deal from the new set. It does Mill but it get rid of their entire hand and forces them to draw more (in a weird way this fulfills your goal). Also I would add Phenax, God of Deception and Triton Tactics. This allows you, with Phenax out, to tap two guys to mill and with their abilities on the stack, play Triton Tactics on them. Allow Tactics to resolve and them tap them again for the Phenax ability. You just milled a ton of cards now. Also remember with this, The first activation of the mill ability wont check the toughness of the creatures until it resolves so both activation's will be for the same higher toughness amount.