The best practice is to share data by placing it into a repository because you don't have to do any work after submission! Most repositories also have built-in methods for data citation and providing data permanence.
Here are some suggested repositories:
You can find other repositories listed by discipline at:
Plan to perform quality control and add documentation to your data prior to sharing either for a collaboration or publicly. These steps make it easier for someone to understand and use your data.
For tabular data, consider using OpenRefine for data clean up.