The 4 Essentials For Volunteering/Internships:
Always bring lots of water and snacks.
Wear comfortable clothing and footwear. Oftentimes you will be active for extended periods of time.
Have a positive attitude and a productive mindset.
Make sure you always show up on time. Remember that early is always better!
Most volunteer roles and internships require you to be collaborative, social, and sometimes even work in groups. Even if you think you don't have the best social skills, challenge yourself to work with new people because it can truly be one of the most rewarding things from these experiences. You'll also likely learn valuable time management skills, teamwork, and practical problem-solving lessons. When it comes to volunteering, the more you put in the more you'll get out!
These 2 websites provide additional information on what to do and expect before you volunteer:
https://www.volgistics.com/blog/how-to-prepare-for-your-volunteer-experience/
https://www.fastcompany.com/3041347/5-things-you-should-know-before-you-volunteer