In Michaelmas Term 2022, I delivered a series of workshops for OUTTS, the Oxford University Technical Theatre Society. Here are some condensed notes, based on those workshops.
The discussion of contact mics I made in the session was only an overview - there is so much to say on the topic. Contact mics are cheap and fun DIY projects. The parts you need to make one can be bought very cheaply: https://www.zachpoff.com/resources/building-contact-mics/
Some further advice on their usage can be found here: https://www.musicofsound.co.nz/blog/the-first-rule-of-contact-mic-club
One local maker of contact mics is Jez Riley French - he’s a respected UK based sound artist with lots of interesting and inspiring writing on field recording and more! https://jezrileyfrench.co.uk/contact-microphones.php
Some of my go-to websites for free, public-domain or otherwise permissively licensed sound effects are:
I generally advise against finding sound effects on YouTube. When browsing free sound websites, keep an eye out in particular for public domain licenses such as CC0, CC-PD and similar - these licenses are very permissive compared to, for example, CC-NY-SA or similar. Even if they are free to access, you must always respect the license conditions associated with downloaded sounds.
It is your responsibility to make sure your sampling of music in performances is legal. Gareth Fry wrote a fantastic guide to managing this.