Step 4: Shape up and shut up
Put on a dust mask, then take off the corners with a radius router bit to save on sanding later. If you don't have a router, you could use a jack plane for the more traditional feel. Then crack out an electric sander with some 60 or 80 grit paper and get shaping the wood so that it is nice and round and smooth. And wear some goggles, as the dust goes everywhere. Finish it with some 240 grit paper for a nice smooth finish. Clean the wood with a slightly damp cloth to remove all debris and allow to dry.
My piece of pine is very light in colour, the Nimbus 2000 is mahogany. So stain the wood with a mahogany wood stain. If you can find a mahogany wood varnish, that is good too as it adds a lovely shine to the wood but takes days to dry and is difficult to apply evenly. I mixed up some French Enamel Varnish (FEV) to the right shade and brushed it on swiftly as one coat. If it dries and you run the brush over again, it will become darker with successive coats, so be careful. Your broom will be a lovely dark colour and look great as a walking stick if you wanted to stop now.