You will needA zipped bag (Mine was actually made from strong paper and came from this Ebay seller)
Paper (If your bag isn't made from it, like mine)
Craft Mount (Again, if your bag isn't made from paper)
Pencil and eraser
Felt tips (as many colours as possible. Mine were spares from home and a bog standard Crayola set from Hobbycraft costing £3.99)
Clear car lacquer
Very Easy...And I bet there you were thinking colouring in was for kids!
TimeMine took about 5 hours but it depends on the designs you choose to do.
Operation cut, stick 'n' colour...
If you aren't working straight onto paper, craft mount a sheet to the front and back of your bag, even if you're not doing both sides, just for consistency. Use your pencil and eraser to sketch out your design.
Colour them in (woohoo!)
Blast the whole bag with clear car lacquer.