I suppose it wouldn't do to say "Go slowly Grasshopper".
I have had rather poor success using the white "flint" or Aluminum Oxide sandpaper. It seems to loose its sharpness rapidly or the makers just seem to use poor glue. Whatever the reason, IMO, the Best paper it the orangeish red Garnet paper. If you can find some made by Norton you will have some of the best paper.
The black paper is usually "wet/dry" paper and it is made for sanding metal and paint. It usually doesn't work well on wood.
The black "emery paper" is IMO about the most usless stuff ever invented. Yes, historically it was used a lot but unless your Really into PC, don't bother with it.
One thing that will speed the sanding is to sand across the grain. This should Only be done when there is a lot of wood to remove because it will leave rather nasty scratches on the surface.
The process involves useing 120 grit sandpaper (or courser if you can find it), sanding across the grain until the wood is about 1/32 from the finished locatin. Then use the 120 grit paper to sand WITH THE GRAIN to smooth it and remove the cross scratches. In fact, from this point on, never sand across the grain
When it is smooth and all of the cross scratches are removed, go to a finer paper like 180.
With the 120 and the 180, the last of the material is removed down to where the wood is where you want it to be.
Then finish the whole thing using 220 or 240 paper (still with the grain).
This 220 or 240 paper will not change the shape much if any. It is used only for the final finishing.
Some people use 320 and finer paper to finish with after the 220 paper. I personally don't think it's worth the effort because wood is porous by nature and the openings in the grain are courser than any finish the 320 will produce.
If your working with Maple or other woods you plan on staining, the 320 and finer paper will actually work against you. Why? Because they tend to fill the woods open grain with very fine sand dust which clogs the pores. This prevents the stain from penetrating uniformly.
A thought on sanding blocks.
Use them when your working on surfaces you want to keep flat.
Use them when you want the edge or corner to be sharp.
Much of the beauty of a stock comes from the smooth rounded transitions from one area to another. In other words, flat surfaces are few, and they seldom run into each other leaving sharp corners. Rounded areas may change shape some but they are often best left rounded.
For this reason, it is best to just use your hand or finger to shape the paper and let it smooth and blend the round areas of the stock together. ::
Try to remember, when the gun is finished you will be much happier with a smooth, beautiful piece of wood that takes time, than you will with a hurried, rushed poorly finished piece of wood. :: ::