Masking things Quickly & Perfectly

@JBJB1029 welcome to the community. The answer of your question is "it depends". What do your want to mask? A face? A licence plate? a pimple on a face? And then what do you want the mask to achieve? Blur the face? Change the number on the plate? Remove the pimple? So we need more info. But also you need to be aware that even if some tracking and magic can get you 80% there (as the marketing videos tell you), the last 20% you need to do manually and that takes practice a good eye and experience of how to approach the job.

If you have or can create enough contrast (or an alpha) you can try using Auto Trace  function down near the bottom of the Layer menu.  You would set it to "work area" and, if you have no alpha, a color or luminance.  If it wont work on the video as it is you try adding a contrast or curves effect to try and creat more contrast on the subject.  Depending on the footage it can sometimes do a pretty good job.  Works amazingly for animations with transparency.

We need more information on what you're masking and what the end product will have. AE has some nice masking features but we need more information to answer your question.