1. Find usages
Just press Alt + F7 and get a list of references grouped by type of usage, module and file. This feature is fast and gets you the first results almost immediately. More results appear as the IDE finds them.
By default the results are not grouped by usage type, but you can enable this by pressing Ctrl + Alt + T or by clicking the corresponding button on the sidebar.
If you want to set custom options for the Find Usages algorithm, you can use Shift + Alt + Ctrl + F7 (Shift + Alt + Cmd + F7 for Mac) or click the first button on the right panel with search results.
3. Open in a new tab
If you want to keep the results of previous searches, tell the IDE to open new results in a new tab by checking the Open in new tab option.
4. Quick popup
If you want to see the results quickly without leaving the editor, simply press Alt + Ctrl + F7 (Alt + Cmd + F7 for Mac).
5. Highlight usages, return and throw statements
By default, IntelliJ IDEA highlights the usages of a symbol, return or throw statement at the caret within the opened file in the editor.
However, many developers prefer disabling this feature by deselecting
Settings → Editor → Highlight usages of element at the caret and calling it via Shift + Ctrl + F7 (Shift + Cmd + F7 for Mac) instead, only when you need it. This way you can highlight more than one symbol if you want, and to remove the highlighting by simply pressing Esc.
6. Highlight implemented and overridden methods
Another useful aspect of highlighting usages in IntelliJ IDEA is that you can easily find the methods that are overridden or implemented for a particular class or interface. Just put the caret at the implements or extends statement and press Shift + Ctrl + F7 (Shift + Cmd + F7 for Mac). If there are multiple classes or interfaces, you will be asked whose methods to highlight.