You've seen how the .pro file affects your project's compilation, but there's even more to it than this. If you click on the Projects button on the left of Qt Creator, you'll see the project's options, which consist of the following:
- The Build & Run options
- The Editor options
- The Code Style options
- Dependencies
Each of these is in its own panel.
The final thing that you should know is the build and run kit selector. Qt is one of the best cross-platform toolkits available today...