However you can use as present tense if you are talking as if the person is still alive. For example, in a personal situation when a wife is refusing to believe that the husband is long dead and gone. You see lots of these kind of examples in books and movies. All the previous answers are absolutely correct for ordinary usage.

You can use the present simple to talk about someone who is dead if that person still has an influence or importance today. You can say 'Shakespeare is one of the most famous writers of all time.' Because Shakespeare is still one of the most famous writers. If you use the past simple then you infer that he is no longer one of the most famous writers, unless you put a specific past time expression. 'Shakespeare was the most famous writer of the 17th century.' Otherwise we normally use the past to talk about people who are dead.

Use the past tense to write about a dead person. Example: Jim was a wonderful husband to Jo his wife, a caring father to Mary and Jane and also a compassionate man who was well respected in his community. He helped out whenever he could at the local Homeless Shelter.

It depends whether you are talking about them in short affirmative statements like the ones mentioned by JacquiD, then you will be using mostly the past, unless you are mentioning an enduring quality they possessed. However in a narrative or biography you tend to use the present tense more often,if you start to tell about the person's life in details,his actions, habits etc.Here the writer will be trying to make his account of the events which happened in the past seem more real to the listener,such a vividness requires the usage of the present tense.