Off the bat, Stack coups, save them for lucky board. Once you notice that your power is no longer increasing through the board, just spend into other events like treasure of the sage with big discounts on power items. Ideally in the board you want to stack Medium refines and Charms. Although, CHarms may be the best value from the board since you can stack refines through the monthly event now. NEVER EVER BUY ANYTHING FROM THE SHOP! Only unless you see a good value in the "purchase limit" section of it. Mags will be handed to you over time through practically everything.