You'll spend a lot of time editing, compiling, and debugging your code in Qt Creator, so it's wise to remember the following basics:
The arrow key runs your application without the debugger; to debug your application, choose the arrow key with the bug icon on it.
You can switch between the Editor view and the Debug view of your application by clicking on the Edit or Debug view choice on the left-hand side; if you debug your application, Qt Creator will enter the Debug view automatically.
There's more to breakpoints than just stopping at a line of code! Use data breakpoints to pin down weird bugs that occur only sometimes or to quickly skip over the first bazillion items of a large loop.
The variable pane lets you see more than just the contents of variables; you can also add expressions composed of several variables and arithmetic or view arbitrary memory locations.
Want to hack around a bug during a debugging session? You can change the values...