How descriptions depend largely on your character's POV

I am currently reading Lee Child's A Wanted Man, and once again I am struck by the highly detailed level of descriptions found in this book--as well as the few other Jack Reacher novels I have read.  Then again, given what we know about the character Jack Reacher, being a former MP investigator, he would notice a lot of details because that's what he was trained to do.

Another book which shows a contrast in the level of descriptions is Jeffrey Deaver's The Bone Collector.  In the book, police officer Amelia Sachs has to assist a quadriplegic ex-forensic criminologist named Lincoln Rhyme in collecting evidence at a crime scene.  Amelia doesn't know what she's doing at first, and has to learn evidence collecting the hard way by Lincoln telling her through her headset.  The level of detail is also heavy.

Then again, it should be, given who the characters are.

If your main character is a former CIA agent, they'll probably know how many cars are out front of a cafe and exactly how many people are inside.  A guy, who is a male chauvinist, may always notice the shapely women in the room above anyone else.  If you have someone who is gay, they may notice certain things about a person of the same sex.

Let this run through your mind as you write your book, and hone this as you work on your edits.  You may not at first know what your character is like, but as you go through, you may discover what makes him/her tick, and can refine descriptions based on those discoveries.