Hah, know your drugs & DDIs well including your computer system. Know hotkeys/short cuts for efficiency.
You should already have a system/method of verifying (data entry matching, how you evaluate DURs, documenting, etc.) - learn potential flaws/errors that can arise & incorporate that into your method (this might take some thinking and computer system know how & experience).
Set up your station/supplies in a manner to minimize excessive/unnecessary movements (go in 1 direction with workflow) & stay neat/organized as hell (1 Rx at a time).