get a cardboard box thats slightly bigger than A4 and cut out slightly smaller than A4 holes in said box, tape some white paper (A4) over holes, few table lamps, quick White balance and your set
or get 3 sheets of paper fold each in half staple them together to form 3 sides of a cube, set WB, use flash, then tweak contrast and or curves in photoshop
I used the last method to take this shot: