Dogs, unlike humans, only have sweat glands in their paws, and as such do not need daily bathings as people do. However, their coats will pick up dirt and odors from around, so you should only bathe your dog as often as is needed with the exception of show dogs which may be bathed more often to keep their coat in pristine condition. How often you bathe your dog will depend on the breed, the coat and what your dog's activities are. A show dog may be bathed as much as once a week, but probably can do with much less. Remember that the natural oils secreted by the dog are part of the natural finish of the coat. Brushing the dogs coat can sometimes be far more effective at bringing out the natural sheen than a bath. Shampoo has a tendency to dissolve these natural dog oils - so first brush your dog - and if you feel he needs a bath make sure you get the right shampoo for your dog. If your not sure please invest some money an time in dog grooming books.
Bathing a dog too often may dry out their skin, and that along with shampoo or conditioner residue may cause your dog to itch. Never use human shampoo (it is not suited to a dogs skin and fur), and when selecting a dog shampoo or conditioner look for mild, hypoallergenic brands that will be less likely to cause skin problems. And always remember to rinse your dog thorughly afterwards.
Before bathing your dog you will want to remove as much of the loose overcoat and undercoat as possible and cut out any matting in the hair. If you have been following a regular grooming schedule that shouldn't be much work. Always bath your dog in warm but not hot water and be sure to protect the eyes and ears. It is usually better to start on the dog's head and work your way down. When you are done be sure to rinse the dog's coat thoroughly. Short haired dogs can be quickly dried with an absorbent towel but a pet blow dryer may be more appropriate for long and wire haired dogs.
The amount of brushing a dog requires is again dependant upon the coat and his activities. Dogs with undercoats should be be brushed with both a regular dog brush and an special undercoat brush. Extra brushing should be applied when dog is 'blowing' its undercoat. Regular brushing will distribute the natural oils throughout the coat and lead to a shinier coat. Some wire-haired breed require a different technique know as stripping by (where a small serrated edged knife to is used pull out loose hair).
Trim your pet's nails about once per month. You'll need a clipper designed specifically for the kind of companion animal you have. Either a scissor- or guillotine-style clipper can be used. You should also purchase a small bottle of blood-clotting powder.