Congrats on completing your first d3 visualization! With these basic skills, you can start building more complex visualizations by using some of the D3 pre-packaged methods. There are plenty of visualizations you can leverage now that you understand the mechanisms of how elements are added to the DOM and data is associated with them:

• Selections are array-like data structures that include a reference to the elements with D3 methods and their hierarchy in the DOM. You can create a selection with .selectAll() or a single-item selection with .select()
• The .data(), .enter() and .append() methods all work in unison to create elements and associate their corresponding data with the existing DOM
• The d parameter inside functions used in a D3 context represents the datum associated with the element at hand
• The .attr() and .style() methods allow you to customize the appearance of each element based on data.
• The .on() method can bind an event listener on the elements in the selection.