How tricky can the passive voice be? Not that much: take a look at these exercises and remember: Practice makes perfect!
https://www.englisch-hilfen.de/en/complex_tests/passive1/index.php
https://www.englisch-hilfen.de/en/exercises/active_passive/active_or_passive.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/active_or_passive1.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/form_sentences_simple_past.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/form_sentences_simple_present.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/questions.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/word_order.htm
https://www.englisch-hilfen.de/en/exercises/active_passive/word_order2.htm