In the early game, setup your game by playing only the Eosmon-related engine. Hard play the LV4 Eosmon to play a Menoa for free, and run the LV5 Eosmon engine to grow your board size.
Prioritize fielding all Menoa's as early as possible, followed by [BT5-093] Taichi & Yamato (especially an opponent's LV6 is expected the following turn). Menoa will get you to Phase 2 faster while stabilizing your hand size, and Taichi & Yamato fills your turn with more memory to have a better chance at controlling your opponent's board.
Use the LV6 Eosmon to remove threats, and possibly to field more tamers (if you have a hard time playing them fast enough). It is not important for the LV6 Eosmon to get a clean hit on your opponent's security (despite the high DP and large number of security attacks) as Phase 2 will also pretty much allow for that.
It is also important to keep track of how many cards have been drawn from your deck, and when the counter hits 40 then Phase 1 ends. The ending of Phase 1 means a few things:
– You would have drawn most of the Eosmons/tamers you'd need.
– Subsequent cards in the deck are in the exact order in which you have returned them.