Editing Software Tutorials

As i've previously said we are using Final Cut Pro X to edit our production, I have used this software mant times before so i know the basics however, i'm not 100% sure on how to get that professional, finished film look in an editing software. Such as, the letter box frame, soundtrack and colour correction. So I looked up on youtube for a tutoral and found this one:

Within the first 5 minutes the video shows me how to put the letterbox effect on my clips which is definitly helpful as that's just what i wanted but also gives me even more then what i was hoping to find as it is the whole package on what i need to do, to make my production look professional.