Are there any shortcuts on the keyboard that I can use to speed up the process of serving customers?

F2 – Sale

F3 - Part exchange

F4 – Rental out/Deposit In (Whether you do rentals)

F5 – Return

F6 – Search for the previous record on the product/sales screen.

F7 – Search for the next record on the product/sales screen.

F8 – Payment methods

F9 – Update

F12 – Search

ALT – Toggles between menus.

ARROW KEYS - These are also used to navigate the menu options.

ESC – This closes the current menu

ALT + (Whatever is underlined on the menu screen). For example: On the sales screen details screen if you press and HOLD ALT then press 1 it would move cursor to PART Number. ALT and 2 moves to Account selection