If you have never learned how to sharpen a knife to a razor's edge, get The Razor Edge Book of Sharpening, by John Juranitch. It is the best book on how to sharpen knives, axes, etc. written to date. Then buy two good stones, one medium arkansas, and the other a fine arkansas stone. Use an oxydizer lube like Break Free, or Liquid Wrench to lube the stones when you work on them. Get as long a stone as you can find. Mine are 13" by 3" so I get a good long stroke the lenth of the blade while maintaining a consistent bevel to the edge as I move the blade over the stone.
First use the coarse grit stone to set an approach bevel at a shallow angle. When you have raise a burr the length of the blade from both sides of the blade, go to the fine grit stone, and increase the angle so that you are sharpening only a small portion of the edge you just put on that knife, or razor. Raise a burr- it will be very fine- on that new stone, on both sides of the blade , and then go to the third step, which is to use a leather strop to remove that burr, and polish the edge. Test the resulting edge by dragging it slowly across your thumbnail to feel for any nicks. If you find one, go back to the fine stone and get it out. When you are done, the edge should be able to cut that patch cloth withouthleaving and " fuzz " on the edge of the blade. It will cut quickly, and easily, so if you are not used to having a sharp knife take it slowly the first time you use it. Since cloth can be hard on an edge, keep a leather belt or strop around to polish that edge from time to time while in use. You will be amazed at how long you can go just using a strop before you have to go back to the fine stone to redo the edge.