As with any skill, to get better we need to practice, which, for us, means we need to find data to practice on. There is no best dataset to practice with; rather, each person should find data they are interested in exploring. While this section is by no means comprehensive, it contains resources for data from various topics in the hopes that everyone can find something they want to use.
Unsure of what kind of data to look for? What are some of the things you have wondered about, relating to a topic you find interesting? Has data been collected on this topic, and can you access it? Let your curiosity guide you!