1:You can skip scenes but some might cost u percentage points (you might of known.)
2:You can do an infinate gil trick while O'aka is aboard the Celsius. Once you paid his dept he sells his items for very cheap prices. Buy them and sell them back to make profits, allowing you to get as much as gil you want.
3:On the 40th floor in Via Infinito you obtain a catnip accessory from the Black Elemental, with it you can deal 9999 damage while in yellow HP. Combining the Trigger Happy lvl3 (from the gunner dress sphere.) you can deal over dozens of 9999's making some of the hardest bosses in the game fairly easy.
4:Another one is in use of the LadyLuck dressphere if you want strait 7's then just keep on puasing the game until u do.

And there you go some helpfull tips to you gammers out there