1. Does the application have an Uninstaller? If so, use that.
2. Otherwise, find the app in the Applications Folder and drag it to the trash.
That will get almost all of most apps.
You can also check the Library/Application support for a folder and trash that, and also the Preferences Folders for the tiny pref files.
But really, between 1 and 2 you get 99%.
Regards
TD