Without whaling, the next best thing is multiple accounts. Whether you make new accounts over and over again until you roll one and then keep the account or make a couple of new accounts and stick with them, it pushes the odds more in your favor. I've been playing on my (now lvl 133) main account since day one and it still has zero 6*s. My two alt accounts (lvls 104, 105) have four and three 6*s, respectively. It's almost perverse at this point and I never expect to see a 6* make it to my main account.