Prefix - お／ご - Polite Marker - Increases the politeness of a vocab
By putting お or ご in front of nouns or adjectives, you make the vocab more polite. For example: お母さん (Mother), お茶 (Tea).
The prefix is more often used at some vocab than others. With some vocab (like お茶) it is even considered rude to leave the prefix away.
Note: お is mostly used for vocab with Japanese origin. ご is mostly used for vocab with Chinese origin.
Me and my mom went to the hospital
Are you free on tuesday?
How are you?
Wait in line, please
Meet before you go out
Please fasten your seat belt
That shop has many customers