Observing the night sky
Almost everything that appears to move across the sky at night is Earth rotating underneath it.
A worked example
Watch the same patch of sky for a few weeks. The stars of a constellation hold their pattern, while a planet drifts slowly against them.
The mistake people actually make
A telescope helps mainly by gathering far more light than your eye, which is what makes faint objects visible. City lights brighten the whole sky and hide those faint objects.