how can i increase my deck capacity very faster please help!?

There is no fast way to level up the other gba game before this one called the sacred cards allowed you level up by 15 after each duel in this game they changed it so it had to take a long time the only fast way is to duel tristan the little robot monkey or have a good deck with three dark flare knights and battle the neo ghouls

The best way for me, if you can get past Marik, is to duel Paradox in China. Before you can duel him, you have to get past 5 Millenium Guards. Each one has 3000 LP and with a good deck, is easy to win. Plus you get divine monsters if you ante up. Then you can sell them at the shop for lots of Domino.

Well, what I did, after I got Ra(Phoenix Mode), was to just battle my way through Pegasus' minions (the little green guys who look like pickles with hair)and eventually I got to Pegasus. I just kept battling his minions a ton of times and my deck capacity/duel level got to 2255/290! Alternately, I now battle Espa and ante good cards since he gives cards like Axe Raider, which sell for a lot, and gives 1000-1900 domino points each time, and my level went up about 60 in 2 weeks. Hope it works for you!

Go to the Hall Of Eternity ( You get this by completing the game ) Most of them have about 60 k Life Points, you get 20 deck Capacity per go and 5,000 dominioes, I've gone up 500 levels this week, try to make sure you have ra, then just discard him you should win easy.