Let's start with something simple. Having methods visually separated by a horizontal line helps code readability.
If you want to have the methods visually separated, go to the settings with Control + Alt +S, immediately start typing what we're looking for - "sepa..."
and see how the dialog gradually limits its content to show only the relevant entries in the settings. Check the checkbox for "Show method separators" and you're ready to go.
And as for the tip regarding text search inside the settings dialog - take it as a free bonus tip.
Invoke action by name
Following on the same wave, the proven wisdom goes that search is faster than a look-up. IDEA allows you to invoke commands like refactorings or code generation by name (or just a part of it). To see the magic, choose a block of code worth refactoring and instead of going up into the menu press Control + Shift + A and enter the name of the command you want to perform. Wild cards or incomplete names are of course allowed.
Faster than scanning the menu, I'm certain.
Go To Symbol
The last example of the same search-over-navigation principle. Searching for a method or a variable you only know a name of or a part of it, but can't remember in which file/class it is defined? The Control + Alt + Shift + N key shortcut is a quick way to search for such an element in your project.
No matter how deep it has hid, you'll get it.
Highlight element at caret
This is a feature I've gradually grown into liking. Having all occurrences of the element you're looking at instantly highlighted in the editor can be a great help for some.
Copying a block of code or applying a refactoring requires you to select a piece of code for these actions to operate on. Using Control + W to expand selection around caret and Control + Shift + W to shrink it you make sure you always select a semantically valid block of code.
It is as easy as that, in all supported languages, not only Java.
Compare with clipboard
The last trick for today: now when you know how to effectively select a block of code, how about comparing it with the snippet you've just received from your colleague by email? Or with the class in the org.project.used.but.unmainteintable package? IDEA allows you to quickly compare a selected block of code with the content of the clipboard. In fact it goes further than that. You get a complete merge tool, allowing you to make changes to your code or copy and remove distinct pieces of code as blocks.
Refreshing the knowledge from earlier, remember the shortcut for invoking a command by name?
[Control + Shift + A, you're correct]
And here's the merge tool:
These were some of the small shiny productivity pearls I wanted to show today. What are your favorite little IDEA tricks? Let others know in the discussion!