I build mine in the game based on card availability as the Starter Deck given is not very strong. I spent most of the DP on the DT packs and the best monsters you can get are Synchros like Brionac, Mist Wurm, AOJ Catastor and Goyo Guardian as well as tuners like Mist Valley Soldier and X-Saber Airbellum. Mist Valley Soldier also works well with the Icarus Attack which I recommend transferring over to the main from sidedeck. When your tuners are all 3-4 stars, you need to use weenies that can survive and the starter deck's Nimble Momonga does the job well. Powered Tuner given in the starter deck also works with so many tuners available.
http://yugioh.wikia.com/wiki/Duel_Terminal_-_Synchro_Awakening!!
Notable cards: Cyber Dragon, X-Saber Airbellum, Mist Valley Soldier, Brionac, Mist Wurm, X-Saber Urbellum, AOJ Catastor and Dust Tornado
http://yugioh.wikia.com/wiki/Duel_Terminal_-_Invasion_of_Worms!!
Notable cards: Goyo Guardian and MST
Remember to check for the cards available in the packs before buying as the follow their real world counterpart namesake. I recommend buying half a box each time to see if you already get the cards you require. For spell and trap staples, I get them one of the Structure Deck (SD). Zombie Madness makes a good choice for that lone SD you can buy before completing the game as it contains a good number of staples like Heavy Storm and Torrential Tribute. Check the in-game recipe viewer and you will see the cards available in SDs.
Another tip for the game is to talk to everyone you see at least once like RPG games because some Non-Playable Character (NPC) give useful tips and hints. Move to all corners of the area and look out for yellow arrows showing that some objects that can be checked for treasure. I'll update again when my deck evolves again and I think it should be to Lightsworns when Light of Destruction is unlocked later in story mode!
Updates: I manage to defeat Peko, a girl in Satellite, consecutively 3 times in Structure Deck duels (used Spellcaster's Judgement, Warrior's Triumph and Zombie Madness) to unlock Absolute Powerforce. After buying 1 and a half box of those packs, I manage to form an X-Saber Beat Deck, the second deck after Tuner Beat, with the Saber Holes and Garsem and the DT X-Saber monsters. Unfortunately, I could not get a single Hyunlei.
