There are many ways to portray, present, or convey the message of death. Many poets and authors create a setting of winter to surround the characters or to represent the aging process. For example, John Knowles writes about fun and wonderful times in youth during the summer in his novel "A Separate Peace". Then, terrible trials and death happen during the winter-time. Also, whenever there a death or funeral is about to happen, a storm usually comes in to set the dark mood.
There are other symbols of death that one can insert into a story. There are religious symbols that represent death like crosses or tombs. Having characters walk through a cemetary could also portray death. Make a list of other symbols that you associate with death to trigger other ideas.
It can be portrayed in many different ways. One of them being a sad or negative approach to death, shown through how the characters react, the situation etc. Another way is in a moderate, happy or positive way, again shown through reaction, emotion, scene and situation.
It could of course, also be portrayed in a more imaginitive way-metaphorically.