Good to see a fellow Aussie picking up the game as well, although I am currently in a lull and not playing at all.

You should definitely be looking to join a guild, besides the Guild DEC bonus for wins, the most important aspect would be Brawls. They are great fun and you can earn cards in the process that will help with your CP.

What you would like to look for in a Guild is high activity and affordable donations. Some guilds require you to donate regularly to help build the guild up. Find one that suits you and they are totally worth it. Regarding finding an Aussie one, I don't think its necessary unless you want to physically meet up or something....