Snading stix/papers-Lots of different grits.&shapes.And good paint brushes.
Glue-Elmers,super,& epoxy,And of corse your faverate model glue.
A good spru cutter. And a good xacto knife w/#11 blades.-LOTS of blades.
Later you can add a pin vice w/drill bits,saw,dremel tool-the list goes on.
Master the basics first.
Eric