First hone both sides of the blade using a coarse whetstone using motions parallel to the side of the blade until "spiral" is formed at the tip of the blade. Hone this spiral away using the finer side of the whetstone. Remember to use water when honing. Clean and dry the blade.
Clean and dry the blade after every time you use the knife. Keep the knife in its sheath and keep it in a dry place. Treat a carbon steel blade occasionally with cooking oil or paraffin oil. Never wash a knife with a carbon steel blade in a dishwasher. Sharpen the knife regularly in order to avoid time-consuming basic sharpening. Treat the knife sheath with leather conditioner as necessary.