IntelliJ IDEA is a very keyboard centric IDE. One of the nice things about it is how some concepts and shortcuts work all across the IDE so you don't have to think where to use them and where they won't work. One example is the "Alt-Insert" shortcut which is used for inserting stuff. When you are in the editor you get a nice context sensitive menu for inserting pieces of code. However you can also use Alt-Insert in the Project explorer:

And now we are getting to the main tip - using Camel Case in IDEA. Whenever you want to specify a name of a class, file type, variable, etc. you can use Camel Case to get it filled in very fast. So instead of navigating to the "Web Services" node you can simply write "WS" and only nodes whose initial letters start with WS will get displayed:

Similarly you can use Camel Case in the editor:

AIO gets expanded to ArrayIndexOutOfBoundsException by pressing Ctrl-Space - you don't have to search for it anymore. What a time saver!

As I mentioned it is great that you can use all such productivity boosts all across the IDE. So even when you are debugging and you need to write some complex variable name or class name in the watches view, you can still use Camel Case completion:

Again, AIO gets expanded to ArrayIndexOutOfBoundsException:

Develop with pleasure!