Sharpening a knife sounds like the easiest thing in the world to do. You take a knife, you work it over a sharpening stone for a bit, and viola it's sharp again. If it was that easy no one would have been able to write books on the subject, and fathers wouldn't need to teach sons how you keep an edge on a blade. While there are a variety of styles and tricks, the basics of sharpening a knife are fairly simple if someone tells you.
Things You Will Need
Step 1Look at your whetstone to make sure that it's flat. Most of these sharpening stones have a coarse side and a fine side, and if the stone isn't new you're going to see a dip in the middle from where the previous owner sharpened his knives. You need to have a flat sharpening stone, but remember that when you're sharpening you're grinding metal off the knife at the same time you're grinding stone off of the sharpener.
Step 2Pour some water onto your stone. These stones are meant to use water, though some will use oil, to keep the metal burrs and worn off trash from sticking into the sharpener. These tiny metal slivers will mark up your blade, ruining the sharpening even as you stroke.
Set the stone down flat with the coarse side facing up. Hold the knife with the blade pointed away from you at a 12-15 degree angle. Drag the knife towards you while maintaining this angle. Turn the knife around so that the blade is now facing you and hold it at the same angle, pulling it away from you. The friction between the stone and the blade should be rubbing away metal from the blunt blade and honing a sharper edge.
Step 4Sluice the stone with water to wipe away the grit and metal shards. Continue to sharpen the blade on the coarse side until, when you look at the blade, it has gotten noticeably sharper. Flip the stone over to the fine side, making sure again that the stone is flat. Repeat the motions as you did with the coarse side, but set the angle to roughly 19 or 20 degrees. This will add a secondary, "razor" edge to the blade that will make it very sharp. Remember to wash the stone to remove grit while you sharpen.
Sharpening a knife can be a painstaking and sometimes frustrating experience. If you practice though, and if you're careful and observant, you'll get the hang of it soon enough.