Fairly simple, switch on Filevault2 if you haven't done so and if you have a newer OS, then create a new User, call it Admin and give it Admin rights.
Next log out of the normal user account, login into admin and delete the normal user account.
Then just delete the Apps you want, or use uninstallers if there are uninstallers for the Apps.
Last delete the following contents folders.
/Library/caches All contents
/Library/logs All contents
/private/var/folders All folder inside this folder
private/var/logs All contents
Restart, login into Admin, empty trash, don't do anything more like browsing or anything else, just logout after emptying the trash, that's it.