How do you make Python / PostgreSQL faster?

cursor.execute("UPDATE people SET chats_count = chats_count + 1 WHERE id = '%s'" % person_id)

cursor.execute( "INSERT INTO ... VALUES( %(x)s, %(y)s, %(z)s )", {'x':person_id, 'y':time_to_string(time), 'z':channel,} )

insert_statement="""
    INSERT INTO chats(person_id, message_type, created_at, channel)
    VALUES(:person_id,:message_type,:created_at,:channel)
"""

cursor.execute(insert_statement, person_id='person',message_type='msg',created_at=some_date, channel=3)