How do you estimate time of death?

Tempature-The temperature of a body can be used to estimate time of death during the first 24 hours. Core temperature falls gradually with time since death, and depends on body mass, fat distribution and ambient temperature. If the body is discovered before the body temperature has come into equilibrium with the ambient temperature, forensic scientists can estimate the time of death by measuring core temperature of the body. Rigor Mortis- The presence of rigor mortis also assists forensic scientists in determining the time of death. The body muscles will normally be in a relaxed state for the first three hours after death, stiffening between 3 hours and 36 hours, and then becoming relaxed again. However, there is considerable uncertainty in estimates derived from rigor mortis, because the time of onset is highly dependent on the amount of work the muscles had done immediately before death. Insects-The presence of insects in a corpse is a critical clue towards estimating the time of death for bodies dead for longer periods of time. Because flies rapidly discover a body and their development times are predictable under particular environmental conditions, the time of death can be calculated by counting back the days from the state of development of insects living on the corpse.