blade maintenance is a dying art, its easier to run it through a ceramic sharpener or bin the blade and buy a new oneBy 'traditional' I mean by using an oilstone or waterstone. The waterstones are available online from outlets like these or you might have a shop on your local High Street which does them or the oilstone.
Whichever you decide to buy, there are differences in using them, but for the benefit of confusion, I shall assume that you have bought the oilstone, as that's what many of you will find more readily available.
A very sharp knife is a microscopically fine saw, the act of sharpening simply re-sets the teeth of that saw.
OK, we've got an oilstone, some light oil [3-in-1 is fine], some rags, a leather belt and some plasters.
First off, we assess which side of the stone to use; rough or fine, by determining how blunt the blade is.
The stone should be placed flat on a clean surface [the inside of the wooden box it comes in perfect] and shouldn't be able to move around on the bench.
We then need to apply just a few drops of oil onto the stone and smooth this onto the stone's surface with a spare finger.
Presuming we only need to re-touch the edge with the fine side of the stone, we need to place the blade onto the stone at an angle of around 20 degrees and make steady, even strokes with light pressure edge first from the edge nearest the finger guard[choil] to the tip of the blade [guide to blade geometry]. The handle will need to be raised slightly as to keep the tip on the stone due to the changing geometry of the blade/stone interface.
Start by doing between 5 and 10 sweeps of the blade from choil to tip on one side away from you, wipe off the oil then turn the knife over and do the same amount of sweeps toward yourself. Stop here and feel the edge with your thumb tip for burrs on either side of the edge; if there are none, carry on with the sweeps. If there is a burr, don't worry..this is what you want.
Once we have a burr on one edge we need to imagine what our blade looks like from a tip-on perspective. A burr will make the blade look like a ' y ', rather than a 'v'. We just need to straighten this burr out.
Taking note of which side of the blade has the burr on, that is the side we need to concentrate on. Repeat the sweeps, but this time use very light pressure on the blade and check all along the edge for the burr after each sweep. Once the burr has gone, check the other edge for a burr. The burr, if you've used too much pressure on the blade at this last stage has been too much, will have transferred to the other side of the edge; just 'move' the burr so that its hardly detectable on any side. The stone work has finished.
All that's needed now is to give the edge a strop on a leather belt. This will polish the re-set saw teeth for a more durable edge.
Attach one end of the belt to something like a vice or hook so that you can get some tension on it.
Once you've done this you need to hold the other end in your left hand [right hand if left-handed], and make slow, even draws on the blade working spine [blunt side] toward yourself. After each stroke, turn the blade over and push it away from you whilst applying the same light, even pressure you used on the previous stroke. Continue for multiples of 5 or 10 on each side, just for consistency.
Once you've done all this, and you've got yourself a very keen edge, you'll begin to see the skills develop which will stay with you for life, and you'll feel better for learning how it's done.
Try the blade on a sheet of paper; it should cut with pressure alone.