Hi Jessie,

Every opportunity is definitely different and it's always good to tailor your resume/cover letter.

The basics of a cover letter are:

1. Contact information
2. Introduction
3. Sell yourself
4. Conclusion

It sounds like you are having trouble with part 3, aka "selling yourself". If you don't have specific work related items to bring up, I would think about what stands out about you personally and how you are different from other potential candidates. You can talk about how great of a team player you are, your work ethic, your ability to adapt and work in any situation, etc. Use this to show your best self and not always work examples.

Here's something to look at as well: https://resumegenius.com/cover-letters-the-how-to-guide

I hope this helps, good luck!

-Mark