How can an observer from earth distinguish planets from stars?

Answer 1

-- The planets you can see with your naked eye are generally brighter than

a typical star.

-- They also twinkle less than the stars do.

-- Planets appear as small disks even in binoculars or small telescopes, but

stars never do.

-- From one night to the next, or certainly from one week to the next,

the patterns formed by stars don't change, but planets move through

those patterns.