Click the launchpad icon in the dock. Then find the app you want to delete. Click and hold the app you want to delete, then click the x and confirm.
You can also follow these step-by-step instructions for how to delete an app downloaded from the Mac App Store.
If the app can't be delete in Launchpad, it may have an uninstaller. Open Finder, then click on the Applications folder. If your application has a folder, that folder may have an uninstaller. If it does, click the uninstaller to begin the process.
If neither of the above methods work, you can use AppCleaner. This is a step up from dragging the application into the trash because it attempts to find all files associated with the app.