Use the 3-2-1 rule:
- Store 3 copies of your data
- Use at least 2 different storage media (thumb drive, hard drive, cloud storage, etc.)
- Keep 1 copy offsite in a different location
Use an open format (like PDF, CSV or RTF) so you won't ever be stuck with files that you can't open due to software changes
Contact the library for more information about long-term preservation of your research data.