Open Data is research data that can be used, reused, and redistributed freely by anyone—subject at most to the requirement to attribute and share alike.
4 Steps - from the Open Data Handbook
(1) Choose your dataset(s).
Being informed on best practices helps
(2) Apply an open license.
These links will help you choose a license.
(3 & 4) Make data available. Make data discoverable.
-Mantra: keep it simple, move fast, be pragmatic-
Use data repositories