When working with big projects we always come back to 10-20 items/files where we do the most of our work.
IntelliJ IDEA helps you collecting all these items in one place — ‘Favorites’. It’s easy to add a file, a class or a method to the Favorites by simply pressing Alt+Shift+F. You can also drag and drop items to the Favorites.
And now with ‘Favorites’ being a separate tool-window, just press Alt+2 (or Cmd+2) whenever you need to access one of your precious items again.