Choose a glossy or semi-gloss colour that is easy to wipe off. In the hallway, shoes, clothes, bags and the like can easily leave marks on the walls.
Test paint your chosen colour on a piece of cardboard and move it around the room. Then you can see how the colour is perceived in different lights.
Measure the surfaces to be painted so the paint shop can work out how much paint you need.
Remove wall sockets and switches so you don't have to mask them. But remember to cut the power first!
Cover all doorways in the hallway with masking tape to prevent dust from spreading to other rooms. If you like, put plastic sheeting on both sides of the doorway to create a sluice.