Get yourself a box cutter knife, do not try to get the blade too sharp as you don't want to skin the arrow, just remove the old glue. Cleaning shafts afteris explained above.
When fletching the vanes keep within 1/2" to 3/4" from nock, for good arrow flight.
Try not to 'squeeze' the tube of glue as you will have excess glue on the vanes, just let the glue flow itself and try to move smoothly along the'valley' of the vanes. Getting the glue to the side of the vanes will cause the glue to stick to the clamp and when removing the clamp you will also raise the vane away from the arrow. Not good, you'll have to start all over again!
Rub some string wax on the edges of the clamp so as to prevent the 'excess'glue from sticking to the clamp. Make sure the surface edges of the clamp is free of excess glue so the vanes will sit flat in the clamp.
Have fun!