Bugs and cheats listed below can be replicated on a device without the need of cheat tools.
You can still send any S rank staff for the Job Rank Up and get the bonus of +3 in all stats as much as you want. You do this by choosing a lower rank stuff for "Job Rank UP" and then just select the S Rank staff you want use the left/right arrows.
Craft accessory/lunchbox exploit - Allows you to craft beyond your job rank (still requires the cost though).
How the required number of Flower Photos needed to craft the item.
On the initial "What do you want to craft?" screen, choose any accessory that is not greyed-out (to bypass "Job rank too low" error).
Click the left/right arrow buttons beside the "Craft this? ##/##" dialog title until you find the accessory you want to make.