what is the ruling on audience clapping and shoes being upside down

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

The audience's clapping when listening to a lecture or a poem, out of showing admiration and encouragement is permissible, provided that it is not in the mosque, although it is preferable to express admiration and encouragement through other means like Takbeer (saying Allaahu Akbar), or other good words.

With regard to putting the shoes upside down, it is permissible and not forbidden nor disliked.

Allaah Knows best.