some tiny paint brushes for the details, some tweezers, jewelers files, some springy clips for holding parts together or for holding when painting, if you're gonna do the airbrush thing then you'll want some empty paint bottles and some pippets for mixing the paints. Don't forget the right primer for whatever paint you're gonna use. Do a search on how to do oil washes too to really bring out the details in your model.
Grayson72