The criteria used to determine whether something is alive includes movement, growth and

presence of protoplasm, self built organisms, self repair, reproduction and various life process like metabolism, nutrition, respiration, exchange of material, transportation, excretion and irritability.

One good way to remember this is with the acronym MRS GREN;

Movement - The organism can move in some way (plants move as they grow)
Reproduction - Creating new copies of this organism
Sensitivity - A response to a change in the environment around the organism

Growth - The ability to create new structures / cells
Respiration - The ability to break down food to get energy
Excretion - The organism creates waste which is disposed of
Nutrition - The organism has the ability to eat food