Nutrition
Your dog's nutritional requirements will change as he grows from a puppy into an adult dog. Different breeds also have slightly different requirements which you should find out from a vet or a breeder of that specific breed.
Adult dogs do well with two meals a day or one main meal supplemented with dog biscuits, but puppies require more numerous meals. You should feed your dog a nutritionally balanced diet, including constant access to fresh water. You should also feed your dog at set meal times each day as much as possible. Remember to walk them after they eat! Both dry and canned food can provide the same level of nutrition and some dogs have a preference to a certain type. Dry food generally costs less per serving, and stays fresher when left in a bowl all day.
A lot of dogs are naturally greedy and will ask for food constantly. However, you should avoid allowing your dog to become obese as this can cause all sorts of medical problems such as diabetes and joint troubles. Different breeds will weigh different amounts and you should ask your vet if you have any queries about your dog's weight.
Feed your dog in a suitably sized bowl, made of metal or hard plastic with a broad base to avoid spillage. Ensure the bowl is kept clean to avoid a build up of bacteria as dogs do not like to eat off of a dirty plate! Make sure that your dog's water bowl has a plentiful supply of fresh water at all times.
Note: Never feed your dog chocolate as you could end up poisoning them. Chocolate contains a chemical called Theo bromine which can cause vomiting and restlessness in pets. Larger doses can be fatal.